Endogenous codeine and morphine in anorexia and bulimia nervosa

Low levels of proinflammatory cytokines in a transdiagnostic sample of young male and female early onset eating disorders without any previous treatment: A case control study

Growing interest exists in the association of the immune system and its role in the development and maintenance of eating disorders (ED). Current evidence suggests that serum cytokine levels seem to be elevated in females with anorexia nervosa (AN). However, less is known in bulimia nervosa (BN) and other specified feeding and eating disorders (OSFED), specially in males. We aimed to perform a case-control study in a sample of forty eight young patients (38 females and 10 males) with early diagnosis of AN, BN or OSFED and without any previous treatment, compared with twenty nine healthy controls (19 females and 10 males) matched by age, sex and socioeconomic status. We evaluated eating-related psychopathology and depressive symptoms and measured serum concentration of proinflammatory cytokines IL-1β, IL-6, and TNF-α and anti-inflammatory cytokine IL-10. Contrary to expectations, levels of IL-1β and IL-6 were significantly lower in ED patients, compared with healthy controls. Comparing the different groups of females, we found elevated levels of IL-10 among ED patients therefore supporting the idea of an immunosuppressive status in the early stages. This could indicate that early onset patients without any previous treatment could remain in a reward-dependent state with a lower immune response.

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

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

Decreased cerebral opioid receptors availability related to hormonal and psychometric profile in restrictive-type anorexia nervosa

PURPOSE

The opioid system role in anorexia nervosa (AN) pathophysiology is still unclear since conflicting results were reported on peripheral and cerebrospinal fluid opioids levels. The study main aim was to evaluate cerebral AN opiate receptor availability by using [¹¹C] diprenorphine, a ligand with non-selective binding.

METHODS

In vivo [¹¹C]diprenorphine cerebral non-displaceable binding potential (BP_ND) evaluated by PET imaging was compared between three groups : 17 undernourished restrictive-type AN patients (LeanAN), 15 AN patients having regained normal weight (RecAN) and 15 controls. A lower BP_ND may account for an increased opioid tone and vice versa. Serum hormones and endogenous opioids levels, eating-related and unspecific psychological traits were also evaluated.

RESULTS

Compared to controls, LeanAN and RecAN patients had decreased [¹¹C]diprenorphine BP_ND in middle frontal gyrus, temporo-parietal cortices, anterior cingulate cortex and in left accumbens nucleus. Hypothalamo-pituitary (H-P), left amygdala and insula BP_ND was found decreased only in LeanAN and that of putamen only in RecAN. LeanAN presented higher dynorphin A and enkephalin serum levels than in controls or RecAN. Inverse correlations were found in total group between : 24 h mean serum cortisol levels and anterior cingulate gyrus or insula BP_ND; eating concern score and left amygdala BP_ND. Positive correlation were found between leptin and hypothamus BP_ND; LH and pituitary BP_ND.

CONCLUSIONS

Low opiate receptor availability may be interpreted as an increased opioid tone in areas associated with both reward/aversive system in both AN groups. The relationship between the opioid receptors activity and hypercorticism or specific psychometric scores in some of these regions suggests adaptive mechanisms facing anxiety but also may play a role in the disease perpetuation.

New Insights in Anorexia Nervosa

Anorexia nervosa (AN) is classically defined as a condition in which an abnormally low body weight is associated with an intense fear of gaining weight and distorted cognitions regarding weight, shape, and drive for thinness. This article reviews recent evidences from physiology, genetics, epigenetics, and brain imaging which allow to consider AN as an abnormality of reward pathways or an attempt to preserve mental homeostasis. Special emphasis is put on ghrelino-resistance and the importance of orexigenic peptides of the lateral hypothalamus, the gut microbiota and a dysimmune disorder of neuropeptide signaling. Physiological processes, secondary to underlying, and premorbid vulnerability factors-the "pondero-nutritional-feeding basements"- are also discussed.

Endogenous morphine-6-glucuronide (M6G) is present in the plasma of patients: validation of a specific anti-M6G antibody for clinical and basic research

Endogenous morphine and its derivatives (morphine-6-glucuronide [M6G]; morphine-3-glucuronide [M3G]) are formed by mammalian cells from dopamine. Changes in the concentrations of endogenous morphine have been demonstrated in several pathologies (sepsis, Parkinson's disease, etc.), and they might be relevant as pathological markers. While endogenous morphine levels are detectable using enzyme-linked immunosorbant assay (ELISA), mass spectrometry (MS) analysis was, so far, the only approach to detect and quantify M6G. This study describes the preparation of a specific anti-M6G rabbit polyclonal antibody and its validation. The specificity of this antibody was assessed against 30 morphine-related compounds. Then, a M6G-specific ELISA-assay was tested to quantify M6G in the plasma of healthy donors, morphine-treated, and critically ill patients. The antibody raised against M6G displays a strong affinity for M6G, codeine-6-glucuronide, and morphine-3-6-glucuronide, whereas only weak cross-reactivities were observed for the other compounds. Both M6G-ELISA and LC-MS/MS approaches revealed the absence of M6G in the plasma of healthy donors (controls, n = 8). In all positive donors treated with morphine-patch (n = 5), M6G was detected using both M6G-ELISA and LC-MS/MS analysis. Finally, in a study on critically ill patients with circulating endogenous morphine (n = 26), LC-MS/MS analysis revealed that 73% of the positive-patients (19 of 26), corresponding to high M6G-levels in M6G-ELISA, contained M6G. In conclusion, we show that endogenous M6G can be found at higher levels than morphine in the blood of morphine-naive patients. With respect to the interest of measuring endogenous M6G in pathologies, we provide evidences that our ELISA procedure represents a powerful tool as it can easily and specifically detect endogenous M6G levels.

Convergent dysregulation of frontal cortical cognitive and reward systems in eating disorders

A substantive literature has drawn a compelling case for the functional involvement of mesolimbic/prefrontal cortical neural reward systems in normative control of eating and in the etiology and persistence of severe eating disorders that affect diverse human populations. Presently, we provide a short review that develops an equally compelling case for the importance of dysregulated frontal cortical cognitive neural networks acting in concert with regional reward systems in the regulation of complex eating behaviors and in the presentation of complex pathophysiological symptoms associated with major eating disorders. Our goal is to highlight working models of major eating disorders that incorporate complementary approaches to elucidate functionally interactive neural circuits defined by their regulatory neurochemical phenotypes. Importantly, we also review evidence-based linkages between widely studied psychiatric and neurodegenerative syndromes (e.g., autism spectrum disorders and Parkinson’s disease) and co-morbid eating disorders to elucidate basic mechanisms involving dopaminergic transmission and its regulation by endogenously expressed morphine in these same cortical regions.

Dysregulation of brain reward systems in eating disorders: neurochemical information from animal models of binge eating, bulimia nervosa, and anorexia nervosa

Food intake is mediated, in part, through brain pathways for motivation and reinforcement. Dysregulation of these pathways may underlay some of the behaviors exhibited by patients with eating disorders. Research using animal models of eating disorders has greatly contributed to the detailed study of potential brain mechanisms that many underlie the causes or consequences of aberrant eating behaviors. This review focuses on neurochemical evidence of reward-related brain dysfunctions obtained through animal models of binge eating, bulimia nervosa, or anorexia nervosa. The findings suggest that alterations in dopamine (DA), acetylcholine (ACh) and opioid systems in reward-related brain areas occur in response to binge eating of palatable foods. Moreover, animal models of bulimia nervosa suggest that while bingeing on palatable food releases DA, purging attenuates the release of ACh that might otherwise signal satiety. Animal models of anorexia nervosa suggest that restricted access to food enhances the reinforcing effects of DA when the animal does eat. The activity-based anorexia model suggests alterations in mesolimbic DA and serotonin occur as a result of restricted eating coupled with excessive wheel running. These findings with animal models complement data obtained through neuroimaging and pharmacotherapy studies of clinical populations. Information on the neurochemical consequences of the behaviors associated with these eating disorders will be useful in understanding these complex disorders and may inform future therapeutic approaches, as discussed here. This article is part of a Special Issue entitled 'Central Control of Food Intake'.

The effects of opioids and opioid analogs on animal and human endocrine systems

Opioid abuse has increased in the last decade, primarily as a result of increased access to prescription opioids. Physicians are also increasingly administering opioid analgesics for noncancer chronic pain. Thus, knowledge of the long-term consequences of opioid use/abuse has important implications for fully evaluating the clinical usefulness of opioid medications. Many studies have examined the effect of opioids on the endocrine system; however, a systematic review of the endocrine actions of opioids in both humans and animals has, to our knowledge, not been published since 1984. Thus, we reviewed the literature on the effect of opioids on the endocrine system. We included both acute and chronic effects of opioids, with the majority of the studies done on the acute effects although chronic effects are more physiologically relevant. In humans and laboratory animals, opioids generally increase GH and prolactin and decrease LH, testosterone, estradiol, and oxytocin. In humans, opioids increase TSH, whereas in rodents, TSH is decreased. In both rodents and humans, the reports of effects of opioids on arginine vasopressin and ACTH are conflicting. Opioids act preferentially at different receptor sites leading to stimulatory or inhibitory effects on hormone release. Increasing opioid abuse primarily leads to hypogonadism but may also affect the secretion of other pituitary hormones. The potential consequences of hypogonadism include decreased libido and erectile dysfunction in men, oligomenorrhea or amenorrhea in women, and bone loss or infertility in both sexes. Opioids may increase or decrease food intake, depending on the type of opioid and the duration of action. Additionally, opioids may act through the sympathetic nervous system to cause hyperglycemia and impaired insulin secretion. In this review, recent information regarding endocrine disorders among opioid abusers is presented.

Intérêt de la nutrition entérale par sonde nasogastrique dans la boulimie

OBJECTIVE

Few effective treatments are available for severe forms of bulimia nervosa, which are accompanied by malnutrition, anxiety, and depressive mood. We previously showed in an open study that nasogastric tube feeding (TF) reduced binges and purging in patients with anorexia nervosa.

METHODS

This prospective randomized trial compared bulimia patients in two treatment groups: one group received TF at home, together with psychotherapy, nutritional counseling and a support group while the control group received only psychotherapy, nutritional counseling, and a support group. Patients in the first group underwent TF for 8 weeks (exclusively for 10 days and associated with meals thereafter). Assessment was based on clinical examination, laboratory results, and a variety of questionnaires (our in-house instrument for measuring binge and vomiting episodes, eating disorder inventory, Beck's depression inventory and the Hamilton rating scale for anxiety), all performed at the onset of treatment and at 8 days, 8 weeks (i.e., the end of TF), and 3 months after treatment began.

RESULTS

Binges and vomiting disappeared faster and more frequently in TF patients than in the control group: 65% versus 29% (p<0.01). Three months later, these remained less frequent in the TF group than among controls (52% versus 33%, p=0.064). Nutritional status, depression, and anxiety improved more among the TF than control subjects (p<0.05).

CONCLUSION

Tube feeding was effective in these patients with bulimia nervosa, reducing the number of binge and vomiting episodes and improving nutritional status and mood.

Do anorectic men share personality traits with opiate dependent men? A case-control study

BACKGROUND

Eating disorders (ED) and substance use disorders (SUD) display clinical and psychodynamic analogies. The co-diagnosis of a substance use disorder in male ED patients is frequent. Nevertheless, knowledge about the mutual predisposing factors or personality analogies is currently scarce and hypotheses are controversial.

METHODS

The Temperament and Character Inventory (TCI) was used to assess 21 anorectic men, 79 heroin-dependent men, and 75 control men matched for age and education.

RESULTS

Anorectic and opiate-addicted patients displayed higher Harm Avoidance and lower Self-directedness and Cooperativeness. Anorectic men displayed lower Reward Dependence and higher Persistence. Opiate addicts had higher Novelty Seeking and Self-transcendence.

DISCUSSION

Anorectic and heroine-dependent subjects share personality traits related to anxiety, fearfulness and antisocial features. Nevertheless, the personality profile does not completely overlap and this could influence the choice of the "substance" of abuse and the related clinical differences between anorexia and heroin dependence.

Laparophobia: a cognitive perspective on appetite control in anorexia nervosa

Decades of research have demonstrated that anorexia nervosa (AN) may be associated with aberrant cognition, yet, its role in maintaining stringent dieting has received relatively little attention from mainstream researchers of eating disorders. The purpose of the present article is to highlight cognitive ('top-down') factors that are considered responsible for anticipatory anxiety of stoutness and frank fat-phobia (laparophobia). A cognitive model proposed departs from the formulation suggesting that phobia of over-eating is superimposed on avoidant tendencies ('environmental autonomy syndrome'), whereas excessive exercising becomes a natural coping strategy with laparophobia, an instrument of reward. AN ideation involves complex neuronal circuitries and multiple neurochemical components that may conceivably represent a mirror image of those underlying obesity. The emphasis on phobia and aberrant membrane excitability akin to channelopathies behoves the clinicians to be aware of potential uses of drugs acting at the gamma-aminobutyric acid and the N-methyl-D-aspartate/AMPA [2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid] receptors sites as the adjuncts to conventional agents in managing AN.

[The auto-addictive hypothesis of pathological eating disorders]

The pathogenic role of self-addiction. Addiction to an endogenous chemical is a new paradigm termed 'self-addiction'. It may contribute to the development of certain habits, the pathological nature of which may set-in on the basis of this "self-addictive"dimension. Pathological eating habits could be inscribed in this perspective. Two extreme situations. In well-fed populations, the ingestion of food does not represent a limiting phase in the global feeding process. Its pathological management may, however, lead to two extreme situations: the absence of ingestion (anorexia) and excessive ingestion (bulimia). In favour of the self-addictive hypothesis. Eating disorders are associated with abnormal levels of endorphins and share clinical similarities with psychoactive drug abuse. The key role of endorphins has recently been demonstrated in animals with regard to certain aspects of normal, pathological and experimental eating habits (food restriction combined with stress, locomotor hyperactivity). The factors leading to pathological eating habits. Neurobiological bases for eating disorders and their durability have recently come to light in the recent implication of abnormalities in the recompense system in the onset of addiction. The endorphin self-addictive model in fact appears the most pertinent with regard to the clinical profile of eating habits and integrates the role of stress.

Chewing and spitting in eating disorders and its relationship to binge eating

OBJECTIVE

This study examined (i) the frequency of chewing and spitting and (ii) its association with other pathological eating behaviors in eating-disordered inpatients. We hypothesized a positive association between chewing and spitting and binge eating given the phenomenological similarities between these disordered eating behaviors.

METHOD

Frequent chewers/spitters were compared with those who did not regularly engage in this behavior with regard to diagnosis, psychometric test results, and associated eating pathology.

RESULTS

Chewing and spitting was not associated with elevated bingeing. Rather, frequent chewers/spitters exhibited higher levels of restrictive eating behaviors and the behavior was more prevalent in younger patients.

DISCUSSION

Contrary to our predictions, chewing and spitting is more closely associated with restrictive than with binge behaviors. This suggests that most individuals chew and spit small portions of food. The behavior is frequent, occurs across diagnostic groups, and may be associated with greater psychopathology. Future studies should clarify the amount of food consumed during chew/spit episodes and the presence of a sense of loss of control.

Endogenous opiates: 1997

This paper is the twentieth installment of our annual review of research concerning the opiate system. It summarizes papers published during 1997 that studied the behavioral effects of the opiate peptides and antagonists, excluding the purely analgesic effects, although stress-induced analgesia is included. The specific topics covered this year include stress; tolerance and dependence; eating and drinking; alcohol; gastrointestinal, renal, and hepatic function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurologic disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunologic responses; and other behaviors.