Screening for anorexia nervosa via measurement of serum leptin levels

Abstract

Due to their sub-normally low fat mass, leptin levels in patients with acute anorexia nervosa (AN) are well below reference levels for age and sex-matched controls. This hypoleptinemia entails endocrinological and behavioral characteristics observed in AN patients during starvation. We aimed to study the appropriateness of hypoleptinemia as a diagnostic marker for AN by assessing sensitivity, specificity and likelihood ratios for different referral serum leptin levels for predicting anorexia nervosa and healthy leanness. For prediction, we additionally generated a score based on a multivariate logistic model including body mass index (BMI; kg/m²) and leptin level. For this purpose, we measured leptin levels in 74 female patients with acute AN upon admission for inpatient or outpatient treatment. Adolescent and adult patients were recruited according to DSM-IV criteria from two multi-center studies. Additionally, leptin levels were measured in 65 female healthy, lean students. Mean serum leptin level was significantly decreased in patients with AN compared to underweight controls (0.87 ± 0.90 vs. 6.43 ± 3.55 μg/L, p < 0.001). Leptin predicted AN independently of BMI; we confirmed a cutoff value in the range of 2 μg/L as having both high specificity and sensitivity. Hypoleptinemia represents a state marker of acute AN and is useful for a laboratory-based diagnostic screening.

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

“…Leptin levels were severely lower in our AN patients than in controls (~1 vs 15 ng/mL), which coincides with previous reports [20][21][22][23][24]. In physiological conditions, low leptin levels trigger a compensatory increase in food intake and a decrease in energy expenditure, but this mechanism is deranged in AN subjects possibly because of decreased transport of leptin through the blood-to-brain barrier induced by food deprivation [25].…”

Leptin treatment of patients with anorexia nervosa? The urgent need for initiation of clinical studies

“…Subsequent work clearly underscored that hypoleptinemia is a hallmark of acute AN; the levels are well below those of age-matched healthy females [11,12]. Healthy underweight females have sufficient leptin levels to prevent the initiation of the physiological adaptation to starvation; in AN patients subphysiological levels are the trigger for this adaptation.…”

Food as a Bariatric Drug

“…Indeed, as Szabo, Siemes and Wallmichrath point out, 9-tetrahydrocannabinol (CB1) has been shown to elicit euphoria principally by its ability to depress GABAnergic inhibition of dopaminergic neurons in the VTA [21]. Thus, in kind, the anorexia nervosa patient through starvation, decreased leptin [22] and increased CB1 activity, may be able to derive a similar euphoria or relative antidepressant response. If this is the case, it may explain part of the reluctance to eat in the anorexic patient and afford a rationale for part of the "addiction" that such patients have for "anti-food."…”