Treatment of anorexia nervosa with TNF-α down-regulating agents

Anti-Inflammatory Therapy as a Promising Target in Neuropsychiatric Disorders

This chapter analyzes the therapeutic potential of current anti-inflammatory drugs in treating psychiatric diseases from a neuro-immunological perspective. Based on the bidirectional brain-immune system relationship, the rationale is that a dysregulated inflammation contributes to the pathogenesis of psychiatric and neurological disorders, while the immunology function is associated with psychological variables like stress, affective disorders, and psychosis. Under certain social, psychological, and environmental conditions and biological factors, a healthy inflammatory response and the associated "sickness behavior," which are aimed to resolve a physical injury and microbial threat, become harmful to the central nervous system. The features and mechanisms of the inflammatory response are described across the main mental illnesses with a special emphasis on the profile of cytokines and the function of the HPA axis. Next, it is reviewed the potential clinical utility of immunotherapy (cytokine agonists and antagonists), glucocorticoids, unconventional anti-inflammatory agents (statins, minocycline, statins, and polyunsaturated fatty acids (PUFAs)), the nonsteroidal anti-inflammatory drugs (NSAIDs), and particularly celecoxib, a selective cyclooxygenase-2 (Cox-2) inhibitor, as adjuvants of conventional psychiatric medications. The implementation of anti-inflammatory therapies holds great promise in psychiatry. Because the inflammatory background may account for the etiology and/or progression of psychiatric disorders only in a subset of patients, there is a need to elucidate the immune underpinnings of the mental illness progression, relapse, and remission. The identification of immune-related bio-signatures will ideally assist in the stratification of the psychiatric patient to predict the risk of mental disease, the prognosis, and the response to anti-inflammatory therapy.

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.

Novel and ultra-rare damaging variants in neuropeptide signaling are associated with disordered eating behaviors

Objective

Eating disorders develop through a combination of genetic vulnerability and environmental stress, however the genetic basis of this risk is unknown.

Methods

To understand the genetic basis of this risk, we performed whole exome sequencing on 93 unrelated individuals with eating disorders (38 restricted-eating and 55 binge-eating) to identify novel damaging variants. Candidate genes with an excessive burden of predicted damaging variants were then prioritized based upon an unbiased, data-driven bioinformatic analysis. One top candidate pathway was empirically tested for therapeutic potential in a mouse model of binge-like eating.

Results

An excessive burden of novel damaging variants was identified in 186 genes in the restricted-eating group and 245 genes in the binge-eating group. This list is significantly enriched (OR = 4.6, p<0.0001) for genes involved in neuropeptide/neurotrophic pathways implicated in appetite regulation, including neurotensin-, glucagon-like peptide 1- and BDNF-signaling. Administration of the glucagon-like peptide 1 receptor agonist exendin-4 significantly reduced food intake in a mouse model of ‘binge-like’ eating.

Conclusions

These findings implicate ultra-rare and novel damaging variants in neuropeptide/neurotropic factor signaling pathways in the development of eating disorder behaviors and identify glucagon-like peptide 1-receptor agonists as a potential treatment for binge eating.

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.

Inflammatory cytokines and anorexia nervosa: A meta-analysis of cross-sectional and longitudinal studies

OBJECTIVE

Although inflammation is increasingly implicated in psychiatric disorders, less is known about its role in anorexia nervosa (AN), an illness with low body mass index (BMI).

METHODS

We performed a systematic PubMed literature search until 12/31/2013 and meta-analyzed cross-sectional and longitudinal studies comparing circulating pro- and anti-inflammatory cytokines between patients with anorexia nervosa (AN) and healthy controls (HCs) (1) before and (2) after weight gain, and (3) within AN patients before and after weight gain. Standardized mean differences (SMDs)± 95% confidence intervals (CIs) for results from ≥ 2 studies were calculated.

RESULTS

Of 999 initial hits, 22 studies with 924 participants (AN=512, HCs=412) were eligible. Compared to HCs, tumor necrosis factor (TNF)-alpha (SMD=0.35, 95%CI=0.09-0.61, p=0.008), interleukin (IL)1-beta (SMD=0.51, 95%CI=0.18-0.84, p=0.003), IL-6 (SMD=0.43, 95%CI=0.11-0.76, p=0.009), and TNF-receptor-II (SMD=0.42, 95%CI:0.07-0.78, p=0.02) were significantly elevated in AN, while C-reactive protein (SMD=-0.53, 95%CI=-.77, -0.28, p<0.0001) and IL-6 receptor (SMD=-0.85, 95%CI=-1.33, -0.36, p=0.0006) were significantly decreased. No differences were found for TNF-receptor I and TGF-β. Across a subset of eight longitudinal studies (AN=152, HCs=129), significant weight gain (baseline BMI=15.4 ± 1.5, endpoint BMI=18.2 ± 1.6, p<0.0001) was not associated with significant changes in TNF-α, IL-6 and IL1-β. However, after weight gain, IL-6 was not different anymore compared to HCs (SMD=0.06, 95%CI=-0.32, 0.45, p=0.75). In meta-regression, shorter illness duration (p=0.0008), but not younger age (p=0.71) significantly moderated greater IL-6 levels.

CONCLUSION

Despite abnormally low BMI, AN seems to be associated with increased inflammatory cytokines. Whether specific elevated cytokines represent trait or state markers of AN, and whether they could be treatment targets requires further study.

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.