RESUMEN
Serotonin (5-HT) pathways play an important role in the pathophysiology of anorexia nervosa (AN). In this study, we investigated functional characteristics of the platelet 5-HT transporter and platelet 5-HT content in AN patients at various stages of their illness in comparison to healthy control woman (HCW) controlling for the 5-HTTLPR deletion/insertion polymorphism and other confounding variables. Fasting blood samples of 58 acutely underweight AN patients (acAN, BMI = 15.2 ± 1.4), 26 AN patients of the initial acAN sample after short-term/partial weight restoration (BMI = 17.3 ± 0.9), 36 weight-recovered AN patients (recAN, BMI = 20.7 ± 2.2) and 58 HCW (BMI = 21.6 ± 2.0) were assessed for kinetic characteristics of platelet 5-HT uptake (V (max), K (m)) and platelet 5-HT content. Plasma leptin served as an indicator of malnutrition. Mean V (max) and K (m) values were significantly higher in recAN subjects in comparison to HCW (2.05 ± 0.62 vs. 1.66 ± 0.40 nmol 5-HT/10(9) platelets min and 432 ± 215 vs. 315 ± 136 nmol, respectively) but there were no differences in platelet 5-HT content (464.8 ± 210.6 vs. 472.0 ± 162.2 ng 5-HT/10(9) platelets). 5-HT parameters in acAN patients and HCW were similar. 5-HTTLPR variants were not related to 5-HT platelet variables. In the longitudinal part of the study we found significantly increased 5-HT content but unchanged 5-HT uptake in AN patients after short-term/partial weight restoration. Our results highlight the importance of malnutrition for the interpretation of abnormalities in neurotransmitter systems in AN. Changes in platelet 5-HT transporter activity were related to the stage of the illness but not to 5-HTTLPR genotype. Increased V (max) and K (m) in recovered AN patients might mirror adaptive modulations of the 5-HT system.
Asunto(s)
Anorexia Nerviosa/sangre , Anorexia Nerviosa/genética , Plaquetas/metabolismo , Proteínas de Transporte de Serotonina en la Membrana Plasmática/fisiología , Serotonina/análisis , Adolescente , Adulto , Anorexia Nerviosa/fisiopatología , Biomarcadores/sangre , Conducta Alimentaria/fisiología , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Mutación INDEL , Leptina/sangre , Desnutrición/genética , Desnutrición/metabolismo , Desnutrición/fisiopatología , Polimorfismo Genético , Proteínas de Transporte de Serotonina en la Membrana Plasmática/análisis , Proteínas de Transporte de Serotonina en la Membrana Plasmática/genética , Índice de Severidad de la Enfermedad , Delgadez/sangre , Delgadez/genética , Delgadez/fisiopatología , Adulto JovenRESUMEN
OBJECTIVE: Most previous studies investigating amino acid levels in anorexia nervosa (AN) have focused on acutely underweight patients. The present study assessed the availability of aromatic amino acids in the plasma of weight-recovered outpatients with AN (recAN) in comparison to acutely underweight AN patients (acAN) and healthy control woman (HCW). METHOD: Plasma tryptophan (TRP), tyrosine (TYR), and phenylalanine (PHEN) as well as leptin concentration were determined in 32 recAN, 32 acAN, and 32 HCW. RESULTS: Both recAN and acAN patients showed significantly lower levels of TRP and PHEN when compared to HCW. TYR was reduced in acAN patients only. DISCUSSION: Normal weight and normal leptin levels but lower availability of TRP and PHEN in recAN patients might indicate that outside a tightly controlled setting these patients still engage in abnormal eating patterns. Reduced peripheral availability of these precursor amino acids could impact on 5-HT and catecholamine functioning in the brain.
