Update on endocrine disturbances in anorexia nervosa

Clinical Trials Required to Assess Potential Benefits and Side Effects of Treatment of Patients With Anorexia Nervosa With Recombinant Human Leptin

The core phenotype of anorexia nervosa (AN) comprises the age and stage dependent intertwining of both its primary and secondary (i.e., starvation induced) somatic and mental symptoms. Hypoleptinemia acts as a key trigger for the adaptation to starvation by affecting diverse brain regions including the reward system and by induction of alterations of the hypothalamus-pituitary-“target-organ” axes, e.g., resulting in amenorrhea as a characteristic symptom of AN. Particularly, the rat model activity-based anorexia (ABA) convincingly demonstrates the pivotal role of hypoleptinemia in the development of starvation-induced hyperactivity. STAT3 signaling in dopaminergic neurons in the ventral tegmental area (VTA) plays a crucial role in the transmission of the leptin signal in ABA. In patients with AN, an inverted U-shaped relationship has been observed between their serum leptin levels and physical activity. Albeit obese and therewith of a very different phenotype, humans diagnosed with rare congenital leptin deficiency have starvation like symptoms including hypothalamic amenorrhea in females. Over the past 20 years, such patients have been successfully treated with recombinant human (rh) leptin (metreleptin) within a compassionate use program. The extreme hunger of these patients subsides within hours upon initiation of treatment; substantial weight loss and menarche in females ensue after medium term treatment. In contrast, metreleptin had little effect in patients with multifactorial obesity. Small clinical trials have been conducted for hypothalamic amenorrhea and to increase bone mineral density, in which metreleptin proved beneficial. Up to now, metreleptin has not yet been used to treat patients with AN. Metreleptin has been approved by the FDA under strict regulations solely for the treatment of generalized lipodystrophy. The recent approval by the EMA may offer, for the first time, the possibility to treat extremely hyperactive patients with AN off-label. Furthermore, a potential dissection of hypoleptinemia-induced AN symptoms from the primary cognitions and behaviors of these patients could ensue. Accordingly, the aim of this article is to review the current state of the art of leptin in relation to AN to provide the theoretical basis for the initiation of clinical trials for treatment of this eating disorder.

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.

A role for intestinal TLR4-driven inflammatory response during activity-based anorexia

Anorexia nervosa (AN) is associated with low-grade systemic inflammation and altered gut microbiota. However, the molecular origin of the inflammation remains unknown. Toll-like receptors are key regulators of innate immune response and their activation seems also to be involved in the control of food intake. We used activity-based anorexia (ABA) model to investigate the role of TLR4 and its contribution in anorexia-associated low-grade inflammation. Here, we found that ABA affected early the intestinal inflammatory status and the hypothalamic response. Indeed, TLR4 was upregulated both on colonic epithelial cells and intestinal macrophages, leading to elevated downstream mucosal cytokine production. These mucosal changes occurred earlier than hypothalamic changes driving to increased levels of IL-1β and IL-1R1 as well as increased levels of plasma corticosterone. Paradoxically, TLR4-deficient mice exhibited greater vulnerability to ABA with increased mortality rate, suggesting a major contribution of TLR4-mediated responses during ABA-induced weight loss.

Case report on anorexia nervosa

Anorexia nervosa is an eating disorder characterized by excessive restriction on food intake and irrational fear of gaining weight, often accompanied by a distorted body self-perception. It is clinically diagnosed more frequently in females, with type and severity varying with each case. The current report is a case of a 25-year-old female, married for 5 years, educated up to 10(th) standard, a homemaker, hailing from an upper social class Hindu (Marvadi) family, living with husband's family in Urban Bangalore; presented to our tertiary care centre with complaints of gradual loss of weight, recurrent episodes of vomiting, from a period of two years, menstrual irregularities from 1 year and amenorrhea since 6 months, with a probable precipitating factor being husband's critical comment on her weight. Diagnosis of atypical anorexia nervosa was made, with the body mass index (BMI) being 15.6. A multidisciplinary therapeutic approach was employed to facilitate remission. Through this case report the authors call for the attention of general practitioners and other medical practitioners to be aware of the symptomatology of eating disorders as most patients would overtly express somatic conditions similar to the reported case so as to facilitate early psychiatric intervention.

Effect of dronabinol therapy on physical activity in anorexia nervosa: a randomised, controlled trial

PURPOSE

The level of physical activity is inappropriately high in up to 80% of the patients suffering of anorexia nervosa (AN), as a result of conscious efforts to lose weight, affect regulation and biological adaptive changes to starvation induced by hypothermia and neuroendocrine mechanisms. The purposes of this paper were to (1) assess the effect of dronabinol-a synthetic cannabinoid agonist-on physical activity in patients with chronic and stable AN, and to (2) unravel the role of leptin and cortisol in this process.

METHODS

This prospective, randomised, double-blind, crossover study was conducted at a specialised care centre for eating disorders. Twenty-four adult women with AN of at least 5-year duration received either the dronabinol-placebo or placebo-dronabinol sequence. Physical activity was monitored during the fourth week of each intervention. Body weight, leptin and urinary free cortisol excretion were measured repeatedly during the trial. Changes in behavioural dimensions related to AN were assessed by Eating Disorder Inventory-2.

RESULTS

The total duration of physical activity did not change, while its average intensity increased by 20% (P = 0.01) during dronabinol therapy, resulting in an increased energy expenditure with 68.2 kcal/day (P = 0.01) above placebo.

CONCLUSIONS

This randomised, double-blind study revealed that cannabinoid agonist treatment was associated with a modest increase in physical activity in adult women with severe and longstanding AN. Additionally, we detected a strong relationship between the circulating levels of leptin and physical activity in these chronically undernourished patients.

A rat in the labyrinth of anorexia nervosa: contributions of the activity-based anorexia rodent model to the understanding of anorexia nervosa

Activity-based anorexia (ABA) is an analogous animal model of anorexia nervosa where food-restricted rats develop excessive running activity when given free access to a running wheel; their body weight sharply decreases, and finally self-starvation and death ensue unless animals are removed from the experimental conditions. The parallel of this animal model with major signs in the human disorder has been the focus of much attention from researchers and clinicians as a platform for translational research. The paper reviews the historical antecedents of ABA, research characterizing its occurrence, and its main limitations and strengths as a model of AN. As a symptomatic model of AN, the ABA model can provide clinicians with innovative and alternative routes for improving the treatment of AN.

Serum levels of fetal antigen 1 in extreme nutritional States

Objective. Recent data suggest that fetal antigen (FA1) is linked to disorders of body weight. Thus, we measured FA1 serum levels in two extreme nutritional states of morbid obesity (MO) and anorexia nervosa (AN) and monitored its response to weight changes. Design. FA1 and insulin serum concentrations were assessed in a cross-sectional study design at defined time points after gastric restrictive surgery for 25 MO patients and 15 women with AN. Results. Absolute FA1 serum levels were within the assay normal range and were not different between the groups at baseline. However, the ratio of FA1/BMI was significantly higher in AN. FA1 was inversely correlated with BMI before and after weight change in AN, but not in MO patients. In addition, MO patients displayed a significant concomitant decrease of FA1 and insulin with the first 25% of EWL, while in AN patients a significant increase of FA1 was observed in association with weight gain. Conclusion. FA1 is a sensitive indicator of metabolic adaptation during weight change. While FA1 serum levels in humans generally do not correlate with BMI, our results suggest that changes in FA1 serum levels reflect changes in adipose tissue turnover.

Remission of eating disorder during pregnancy: five cases and brief clinical review

Eating disorder during pregnancy is associated with a diversity of adverse outcomes and is of potential danger to both mother and child. There is, however, a tendency for remission of the eating disorder during pregnancy with improvement of symptoms such as restrictive dieting, binging and purging, and some women actually manage to put the disease behind them. This case report describes five women with different eating disorders and focuses on the symptomatology during pregnancy and in the months postpartum. The discussion deals with the possible psychological, social and endocrinological reasons for remission and the subsequent relapse, the definition of recovery and the factors which should alert health care professionals of the at-risk pregnancies in cases of undisclosed eating disorder. Furthermore, therapeutic interventions are proposed.

Leptin, ghrelin, and endocannabinoids: potential therapeutic targets in anorexia nervosa

Anorexia nervosa (AN) has the highest mortality rate between psychiatric disorders, and evidence for managing it is still very limited. So far, pharmacological treatment has focused on a narrow range of drugs and only a few controlled studies have been performed. Furthermore, the studies have been of short duration and included a limited number of subjects, often heterogenic with regard to stage and acute nutritive status. Thus, novel approaches are urgently needed. Body weight homeostasis is tightly regulated throughout life. With the discovery of orexigenic and anorectic signals, an array of new molecular targets to control eating behavior has emerged. This review focuses on recent advances in three important signal systems: leptin, ghrelin, and endocannabinoids toward the identification of potential therapeutical breakthroughs in AN. Our review of the current literature shows that leptin may have therapeutic potentials in promoting restoration of menstrual cycles in weight restored patients, reducing motor restlessness in severely hyperactive patients, and preventing osteoporosis in chronic patients. Ghrelin and endocannabinoids exert orexigenic effects which may facilitate nutritional restoration. Leptin and endocannabinoids may exert antidepressive and anxiolytic effects. Finally, monitoring serum concentration of leptin may be useful in order to prevent refeeding syndrome.

The relationship between skinfold thickness and body mass index in North European Caucasian and East Asian women with anorexia nervosa: implications for diagnosis and management

OBJECTIVE

To investigate the relationship between skinfold thickness and body mass index (BMI) in North European Caucasian and East Asian young women with and without anorexia nervosa (AN) in two countries.

METHOD

Height, weight and skinfold thicknesses were assessed in 137 young women with and without AN, in Australia and Singapore. The relationship between BMI and the sum of triceps, biceps, subscapular and iliac crest skinfolds was analysed with clinical status, ethnicity, age and country of residence as covariates.

RESULTS

For the same BMI, women with AN had significantly smaller sums of skinfolds than women without AN. East Asian women both with and without AN had significantly greater skinfold sums than their North European Caucasian counterparts after adjusting for BMI.

CONCLUSION

Lower BMI goals may be appropriate when managing AN patients of East Asian ancestry and the weight for height diagnostic criterion should be reconsidered for this group.

Current concepts in bone and reproductive health in adolescents with anorexia nervosa

Anorexia nervosa (AN) initiates an adaptive response at the level of the hypothalamus, which results in a complex interplay involving most elements of the neuroendocrine axis. Consequences of onset of disease in adolescence include amenorrhoea, pubertal arrest with potential loss of target height, and osteoporosis with reduced capacity for future attainment of peak bone mass. With recovery, delay in restoration of menses is common. Hormonal therapies for restoration of bone mineral density (BMD) in adolescents have shown limited efficacy. This review will discuss the reproductive endocrine effects of AN in adolescence, and discuss new investigative tools for monitoring restoration of reproductive function and BMD in this population.

Differential response of TRHergic neurons of the hypothalamic paraventricular nucleus (PVN) in female animals submitted to food-restriction or dehydration-induced anorexia and cold exposure

TRH neurons of the hypothalamic paraventricular nucleus (PVN), regulate pituitary-thyroid axis (HPT). Fasting activates expression of orexigenic peptides from the arcuate nucleus, increases corticosterone while reduces leptin, and pro-TRH mRNA levels despite low serum thyroid hormone concentration (tertiary hypothyroidism). TRH synthesis is positively regulated by anorexigenic peptides whose expression is reduced in fasting. The model of dehydration-induced anorexia (DIA) leads to decreased voluntary food intake but peptide expression in the arcuate is similar to forced-food restriction (FFR), where animals remain hungered. We compared the response of HPT axis of female Wistar rats submitted to DIA (2.5% saline solution, food ad libitum, 7 days) with FFR (provided with the amount of food ingested by DIA) and naïve (N) group fed ad libitum, as well as their response to acute cold exposure. Pro-TRH and pro-CRH mRNA levels in the PVN were measured by RT-PCR, TRH content, serum concentration of TSH and thyroid hormones by radioimmunoassay. DIA rats reduced 80% their food consumption compared to N, decreased PVN pro-CRH expression, serum estradiol and leptin levels, increased corticosterone similar to FFR. HPT axis of DIA animals failed to adapt: FFR presented tertiary hypothyroidism and DIA, primary. Response to cold stimulation leading to increased pro-TRH mRNA levels and TRH release was preserved under reduced energy availability in FFR rats but not in DIA, although the dynamics of hormonal release differed: TSH release augmented only in naïve; thyroxine in all but highest in DIA, and triiodothyronine in FFR and DIA suggesting a differential regulation of deiodinases.

Predictors of late menarche and adult height in children with anorexia nervosa

OBJECTIVES

The onset of anorexia nervosa (AN) during childhood can affect the timing of puberty and adult height. The aim of the study was to evaluate the determinants of late menarche and adult height in children with AN.

PATIENTS AND METHODS

We carried out a retrospective, longitudinal, university hospital-based study. All prepubertal or early pubertal girls diagnosed with AN between 1998 and 2002 were selected for the study. Participants (n = 33) were studied at a median age of 21 (19.8-24.3) years. AN was diagnosed at 11.8 (10.7-12.3) years.

RESULTS

Patients with AN reached menarche at significantly greater ages than their mothers [15.4 (13.5-16.8) vs. 13.2 (12.0-14.5) years, P < 0.01]. Chronological age at onset of AN and lowest body mass index (BMI) were important independent predictive factors for delayed menarche (P < 0.01). Adult height was 165.0 (163.0-172.0) cm, 2.5 (-1.5 to 5.0) cm above target height. Twelve patients (36%) did not reach their target height and had a median height deficit of -3.9 cm with respect to their target height. The duration of hospitalization, a marker of disease severity and chronicity, was an independent predictor of the difference between adult height and target height for a given individual (beta coefficient = -0.07; P = 0.01). The other factors studied (i.e. age at onset of AN, pubertal stage at diagnosis of AN, lowest BMI reached, associated comorbidity if any, type of AN, age at menarche) had no significant effect on adult height.

CONCLUSION

The intensity of the disease affects the timing of menarche but not adult height in most patients. Hospitalization, despite often being an effective means of managing AN, does not reduce the impact of AN on growth.

Insulin-like growth factor-1 as an indicator of nutrition during treatment of adolescent girls with eating disorders

AIM

The use of serum insulin-like growth factor-1 (IGF-1) concentrations as an index of nutrition has been analysed in teenage girls with eating disorders and weight loss.

METHOD

Blood samples for analysis of IGF-1 were obtained at 349 assessments of 302 patients and biweekly during 56 treatment periods in 46 patients. IGF-1 was related to body size, weight loss, degree of leanness (BMI standard deviation score) and rate of weight loss.

RESULTS

At assessment, when most of the girls were on a weight-losing course, serum IGF-1 concentrations were low. Weight loss immediately prior to assessment was the most important predictor of IGF-1. Together with measurements of weight, height, weight loss and BMI standard deviation score the rate of weight loss predicted IGF-1 to 32-55%. During treatment when there was net weight gain, IGF-1 increased in parallel with the BMI standard deviation score, a measure of leanness, and was also influenced by the short-term weight trend.

CONCLUSION

The serum IGF-1 concentration is an indicator of nutritional status in adolescents with eating disorders. It is sensitive to short-term weight changes measured in a clinical setting and could be used at assessment and to monitor nutritional rehabilitation.

Bioactive insulin-like growth factor (IGF) I and IGF-binding protein-1 in anorexia nervosa

CONTEXT

Regulation of IGF-I activity appears crucial in anorexia nervosa (AN) during adaptation to chronic starvation as well as during the regenerative processes on nutritional restoration.

OBJECTIVE

The objective of this study was to examine the relationship between IGF-I bioactivity and IGF-binding capacity as expressed as formation of the binary complex of IGF-binding protein-1 (IGFBP-1) and IGF-I in patients with AN at different stages and with different subtypes of the disease.

DESIGN

This was a longitudinal study.

SETTING

The study took place at a clinical research center at a university hospital.

STUDY PARTICIPANTS

We studied a total of 45 women with AN and 24 age-comparable healthy controls.

MAIN OUTCOME MEASURES

IGF-I bioactivity was determined using an IGF-I receptor activation assay, and IGF-I/IGFBP-1 complex formation was determined by an assay that allows direct determination of the binary complex.

RESULTS

IGF-I bioactivity was significantly decreased in serum from patients with AN. We found significant correlations between total, ultrafiltered free, and bioactive IGF-I. Despite increased IGFBP-1 concentrations, levels of IGF-I/IGFBP-1 binary complex were not significantly increased in AN. Oral contraceptives were associated with increased levels of IGF-I, IGFBP-1, and binary complex formation. Ghrelin levels were only significantly raised in those patients who had lost more than 5% of the body weight during the last 4 wk, whereas ghrelin levels in weight-stable as well as in weight-gaining patients did not significantly differ from the controls.

CONCLUSIONS

Total IGF-I level is a suitable marker of IGF-I bioactivity in emaciated patients with AN irrespective of the clinical subtype and acute nutritional state.

The significance of routine laboratory analyses in the assessment of teenage girls with eating disorders and weight loss

Routine laboratory investigations that had been performed at disease assessment on 327 teenage girls with eating disorders and weight loss were analyzed. The laboratory investigations included erythrocyte sedimentation rate (ESR), blood haemoglobin concentration (Hb), white blood cell count (WBC), platelet count, serum alkaline phosphatase (ALP) activity, serum aspartate aminotransferase (ASAT) activity, serum alanine aminotransferase (ALAT) activity, serum albumin concentration, glycated haemoglobin (HbA1c) and serum concentrations of sodium, potassium, magnesium, calcium (corrected for albumin), inorganic phosphate, creatinine and urea. The results were for ESR, Hb, WBC, platelet count, ALP, ASAT, ALAT, inorganic phosphate, creatinine, urea and HBA1C related to weight and (ongoing) weight loss. The variations of the biochemical measurements were, however, largely within reference ranges, weight and weight changes predicted the biochemical measurements only to a small degree and in individual patients the results of the analyses often suggested normality. These analyses may therefore not be suited to assess the degree of weight loss and starvation in eating disorders. They may, however, be useful for the exclusion of other diseases which could show weight loss and biochemical abnormalities.

Free insulin-like growth factors -- measurements and relationships to growth hormone secretion and glucose homeostasis

IGF-I is a multipotent growth factor with important actions on normal tissue growth and regeneration. In addition, IGF-I has been suggested to have beneficial effects on glucose homeostasis due to its glucose lowering and insulin sensitizing actions. However, not all effects of IGF-I are considered to be favorable; thus, epidemiological studies suggest that IGF-I is also involved in the development of common cancers, atherosclerosis and type 2 diabetes. The biological actions of IGF-I are modulated by at least six IGF-binding proteins, which bind approximately 99% of the circulating IGF-I pool. So far, most in vivo studies have used serum or plasma total (extractable IGF-I) as an estimate of the bioactivity of IGF-I in vivo. However, within the last decade, validated assays for measurement of free IGF-I have been described. This review aims to discuss the current assays for free IGF-I and their advances in relation to the traditional measurement of total IGF-I. The literature overview will focus on the role of circulating free versus total IGF-I in the feedback regulation of GH release, and the possible involvement of the circulating IGF-system in glucose homeostasis.

Intestinal permeability is decreased in anorexia nervosa

Malnutrition and absence of exogenous luminal nutrients in the gastrointestinal tract affect intestinal permeability (IP) leading to an increased penetration of substances that passively cross intestinal epithelium via intercellular pathways. We hypothesised that an increase in IP could occur in patients with anorexia nervosa because of their prolonged fasting and chronic malnutrition. Therefore, we assessed IP in 14 drug-free anorexic women and 19 drug-free age-matched healthy women by means of the lactulose/mannitol (LA/MA) test. To this purpose, after an overnight fast, subjects ingested an oral solution containing 5 g lactulose and 2 g mannitol in 100 ml water. Urine specimens were collected immediately before and 30, 60, 120, 180, 240 and 300 min after the ingestion of the sugar solution. Urinary lactulose and mannitol were determined by high-performance anion exchange chromatography coupled with pulsed amperometric detection. We found that IP, as expressed by the 5-h LA/MA excretion ratio, was significantly decreased in anorexic women because of a lower urinary recovery of lactulose. Moreover, in patients, the time course of lactulose excretion significantly differs from healthy controls. These results do not confirm our hypothesis of increased IP in anorexia nervosa. Since IP reflects the anatomo-functional status of intestinal mucosa, the present findings support the idea that changes in the anatomo-physiology of intestinal mucosa occur in anorexia nervosa.

Adapted to flee famine: adding an evolutionary perspective on anorexia nervosa

Anorexia nervosa (AN) is commonly attributed to psychological conflicts, attempts to be fashionably slender, neuroendocrine dysfunction, or some combination of these factors. Considerable research reveals these theories to be incomplete. Psychological and societal factors account for the decision to diet but not for the phenomenology of the disorder; theories of biological defects fail to explain neuroendocrine findings that suggest coordinated physiological mechanisms. This article presents evidence that AN's distinctive symptoms of restricting food, denial of starvation, and hyperactivity are likely to be evolved adaptive mechanisms that facilitated ancestral nomadic foragers leaving depleted environments; genetically susceptible individuals who lose too much weight may trigger these archaic adaptations. This hypothesis accounts for the occurrence of AN-like syndromes in both humans and animals and is consistent with changes observed in the physiology, cognitions, and behavior of patients with AN.