Adipocytokines, gut hormones and growth factors in anorexia nervosa

Lower leptin level at discharge in acute anorexia nervosa is associated with early weight-loss

OBJECTIVE

Predictive values of acute phase metabolic abnormalities of anorexia nervosa (AN) have seldom been studied. As early postrestoration weight loss is associated with poor outcome, discharge biologic parameters were assessed to detect an association with 2-month follow-up weight loss as a proxy to poor outcome.

METHOD

Fasting plasma levels of leptin, acyl-ghrelin, obestatin, PYY, oxytocin and BDNF were measured in 26 inpatients, at inclusion, at discharge and 2 months later. A body mass index less than 18 2-month postdischarge was considered a poor outcome.

RESULTS

Nineteen patients (73%) had a fair outcome and seven (27%) had a poor one with a mean loss of 0.69 versus 4.54 kg, respectively. Only discharge leptin levels were significantly higher in fair versus poor outcome patients (14.1 vs. 7.0 ng/ml, p = 0.006). The logistic regression model using discharge leptin, acyl-ghrelin, obestatin, oxytocin, PYY and BDNF levels as predictors of outcome disclosed a nearly significant effect of leptin (p < 0.10). Receiver operating characteristic analysis showed 11.9 ng/ml was the best value of threshold. Neither clinical variables differed according to outcome.

CONCLUSION

Leptin level may be a biomarker of early weight relapse after acute inpatient treatment of AN. Its clinical usefulness in monitoring care in AN should further be determined.

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.

Inflammatory Markers in Anorexia Nervosa: An Exploratory Study

Inflammation has been suggested to play a pathophysiological role in anorexia nervosa (AN). In this exploratory cross-sectional study, we measured serum concentrations of 40 inflammatory markers (including cytokines, chemokines, and adhesion molecules) and brain-derived neurotrophic factor (BDNF) in people with AN (n = 27) and healthy controls (HCs) (n = 13). Many of these inflammatory markers had not been previously quantified in people with AN. Eating disorder (ED) and general psychopathology symptoms were assessed. Body mass index (BMI) and body composition data were obtained. Interleukin (IL)-6, IL-15, and vascular cell adhesion molecule (VCAM)-1 concentrations were significantly elevated and concentrations of BDNF, tumor necrosis factor (TNF)-β, and vascular endothelial growth factor (VEGF)-A were significantly lower in AN participants compared to HCs. Age, BMI, and percentage body fat mass were identified as potential confounding variables for several of these inflammatory markers. Of particular interest is that most of the quantified markers were unchanged in people with AN, despite them being severely underweight with evident body fat loss, and having clinically significant ED symptoms and severe depression and anxiety symptoms. Future research should examine the replicability of our findings and consider the effect of additional potential confounding variables, such as smoking and physical activity, on the relationship between AN and inflammation.

Immune-metabolic profiling of anorexic patients reveals an anti-oxidant and anti-inflammatory phenotype

CONTEXT

Anorexia nervosa (AN) is an excessive form of calorie restriction (CR) associated with pathological weight loss and alterations of the immune system. However, AN patients seem to be protected from common viral infections.

OBJECTIVES

To investigate the metabolic and molecular adaptations induced by sustained extreme CR in the peripheral blood mononuclear cells (PBMCs) of patients with restrictive alimentary AN.

DESIGN

Inflammatory cytokines and adipokines were measured in 15 young (age range, 15-24 years) AN female patients and 20 age-matched healthy controls. Isolated PBMCs were immunophenotyped by flow cytometry, and glycolysis and mitochondrial respiration were determined by measuring the extracellular acidification and oxygen consumption rate. Stress resistance to H2O2 and the antioxidant transcriptional profile of PBMCs and human fibroblasts incubated with sera from AN patients were also determined.

RESULTS

Compared with controls, AN patients (BMI, 15.9±0.4 kg/m(2)) had significantly fewer leucocytes, lymphocytes and NK cells, lower serum concentrations of leptin, IGF-1 and sTNFR1, and higher levels of adiponectin, sCD40L and sICAM-1 (p<0.05). IL-1β, TNFα, and IL-6 produced by PBMC cultured with autologous serum for 48 h were significantly lower in AN patients than in controls (p<0.01). Moreover, glycolysis and mitochondrial respiration were lower, and the antioxidant transcriptional profile was higher in the PBMCs of AN patients. Fibroblasts cultured in serum from AN patients showed a 24% increase in resistance to H2O2 damage.

CONCLUSIONS

Extreme CR in AN patients is associated with a reduction in several immune cell populations, but with higher antioxidant potential, stress resistance and an anti-inflammatory status.

Peptides from adipose tissue in mental disorders

Adipose tissue is a dynamic endocrine organ that is essential to regulation of metabolism in humans. A new approach to mental disorders led to research on involvement of adipokines in the etiology of mental disorders and mood states and their impact on the health status of psychiatric patients, as well as the effects of treatment for mental health disorders on plasma levels of adipokines. There is evidence that disturbances in adipokine secretion are important in the pathogenesis, clinical presentation and outcome of mental disorders. Admittedly leptin and adiponectin are involved in pathophysiology of depression. A lot of disturbances in secretion and plasma levels of adipokines are observed in eating disorders with a significant impact on the symptoms and course of a disease. It is still a question whether observed dysregulation of adipokines secretion are primary or secondary. Moreover findings in this area are somewhat inconsistent, owing to differences in patient age, sex, socioeconomic status, smoking habits, level of physical activity, eating pathology, general health or medication. This was the rationale for our detailed investigation into the role of the endocrine functions of adipose tissue in mental disorders. It seems that we are continually at the beginning of understanding of the relation between adipose tissue and mental disorders.

Adipocytokine levels in women with anorexia nervosa. Relationship with weight restoration and disease duration

OBJECTIVE

Starvation-induced depletion of fat stores in anorexia nervosa (AN) is known to be accompanied by alterations in some circulating adipocytokines. We analyzed a panel of circulating adipocytokines in women with AN compared with normal-weight controls and their relation with the disease duration and weight restoration.

METHOD

We analyzed circulating adipocytokine levels in 28 patients with AN and in 33 normal-weight controls who were eating healthily. We determined by enzyme-linked immunosorbent assay the circulating levels of total and high molecular weight (HMW) adiponectin, lipocalin-2 (LCN2), leptin, tumor necrosis factor receptor-II (TNFRII), interleukin-6 (IL6), adipocyte fatty acid binding protein-4 (FABP4), ghrelin, and resistin.

RESULTS

The two circulating forms of adiponectin are higher in AN women compared with controls. Both total and HMW adiponectin related negatively to the duration of the disease (r = -0.372, p = 0.033; r = -0.450, p = 0.038, respectively). Furthermore, the lipid binding-proteins LCN2 and FABP4 are lower in AN compared to the control group. Finally, leptin levels are lower in AN against controls and correlated positively with disease duration (r = 0.537, p = 0.007). Resistin, ghrelin, TNFRII, and IL6 have similar values in both groups, although TNFRII and ghrelin related negatively to body mass index variation at the end of treatment (r = -0.456, p = 0.039; r = -0.536, p = 0.015, respectively).

DISCUSSION

These results suggest there is a need to investigate if changes in adipocytokine levels could serve as weight restoration biomarkers. Further studies are warranted to elucidate the specific role of these molecules in the timing of weight restoration.

Serum neurotrophin concentrations in polish adolescent girls with anorexia nervosa

OBJECTIVES

Several lines of evidence suggest that brain-derived neurotrophic factor (BDNF) plays an important role in weight regulation and eating behaviors as well as in the activity-dependent neuroplasticity underlying learning and memory behaviors involving the hippocampus. In anorexia nervosa (AN) patients, abnormal serum BDNF concentrations, cognitive impairments and specific personality traits have been traditionally observed. This study explores the levels of four serum neurotrophins [BDNF, neurotrophin 3 (NTF3), neurotrophin 4 (NTF4) and glial cell line-derived neurotrophic factor (GDNF)] with respect to their use as potential biomarkers for AN. This study also investigates any associations that might exist between serum neurotrophin levels and neurocognitive impairment or personality traits.

METHODS

Serum neurotrophin concentrations were measured in 60 AN patients (AN group) and 45 healthy controls (HC group). We correlated the serum levels of the four neurotrophins BDNF, NTF3, NTF4 and GDNF and the clinical type of anorexia. We also analyzed the relationship between serum neurotrophin levels and the Beck Depression Inventory, body mass index, executive functions by the Wisconsin Card Sorting test (WCST) and personality dimensions by the Temperament and Character Inventory (TCI) test.

RESULTS

Serum NTF4 concentrations were significantly lower when comparing all AN patients (34.7 ± 72.5 pg/ml) or restriction type AN patients (29.1 ± 62.5 pg/ml) with the HC group (58.4 ± 135.8 pg/ml; p = 0.004 and p = 0.005, respectively). A significant correlation (p < 0.005) between BDNF serum levels and patient personality dimensions as measured by the TCI test was observed. Furthermore, significant correlations were observed between NTF4 and GDNF serum levels and executive function as measured by the WCST.

CONCLUSIONS

These data suggest that NTF4 might serve as a biomarker for AN. Furthermore, BDNF and GDNF serum levels appear to be associated with personality traits and executive function.

Gut microbiota composition in male rat models under different nutritional status and physical activity and its association with serum leptin and ghrelin levels

BACKGROUND

Several evidences indicate that gut microbiota is involved in the control of host energy metabolism.

OBJECTIVE

To evaluate the differences in the composition of gut microbiota in rat models under different nutritional status and physical activity and to identify their associations with serum leptin and ghrelin levels.

METHODS

In a case control study, forty male rats were randomly assigned to one of these four experimental groups: ABA group with food restriction and free access to exercise; control ABA group with food restriction and no access to exercise; exercise group with free access to exercise and feed ad libitum and ad libitum group without access to exercise and feed ad libitum. The fecal bacteria composition was investigated by PCR-denaturing gradient gel electrophoresis and real-time qPCR.

RESULTS

In restricted eaters, we have found a significant increase in the number of Proteobacteria, Bacteroides, Clostridium, Enterococcus, Prevotella and M. smithii and a significant decrease in the quantities of Actinobacteria, Firmicutes, Bacteroidetes, B. coccoides-E. rectale group, Lactobacillus and Bifidobacterium with respect to unrestricted eaters. Moreover, a significant increase in the number of Lactobacillus, Bifidobacterium and B. coccoides-E. rectale group was observed in exercise group with respect to the rest of groups. We also found a significant positive correlation between the quantity of Bifidobacterium and Lactobacillus and serum leptin levels, and a significant and negative correlation among the number of Clostridium, Bacteroides and Prevotella and serum leptin levels in all experimental groups. Furthermore, serum ghrelin levels were negatively correlated with the quantity of Bifidobacterium, Lactobacillus and B. coccoides-Eubacterium rectale group and positively correlated with the number of Bacteroides and Prevotella.

CONCLUSIONS

Nutritional status and physical activity alter gut microbiota composition affecting the diversity and similarity. This study highlights the associations between gut microbiota and appetite-regulating hormones that may be important in terms of satiety and host metabolism.

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.