Reduced Plasma Apelin lvgs in ASD

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Archives of Medical Research

Reduced Plasma Apelin Levels in Patients with Autistic Spectrum Disorder

nna Bosoa, 1, Enzo Emanueleb, , 1, , Pierluigi Politia, Alessandro

Pacea, rosa Arrab, Stefania Ucelli di Nemia and Francesco Baralea

aDepartment of Health Sciences, Section of Psychiatry

bInterdepartment Center for Research in Molecular Medicine (CIRMC),

University of Pavia, Pavia, Italy

Received 7 June 2006; accepted 9 August 2006. (ARCMED-D-06-00238).

Available online 3 November 2006.

Background

Dysregulation of the vasopressin (AVP) system has been implicated in the

pathogenesis of autistic spectrum disorder (ASD). Apelin is a recently

discovered neuropeptide that could counteract AVP actions and whose

receptors are colocalized with vasopressin in hypothalamic magnocellular

neurons. Aims of the present study were to investigate circulating

levels of apelin in patients with ASD and to assess their correlation

with plasma AVP concentrations.

Methods

Plasma levels of apelin and AVP were measured in a total of 18 patients

with ASD and 21 age- and gender-matched healthy comparison subjects. The

Childhood Autism Rating Scale (CARS) was used to assess the severity of

autistic symptoms.

Results

Significantly reduced levels of apelin (p <0.001) and elevated

concentrations of AVP (p = 0.02) were found in ASD patients as compared

to controls. Additionally, a significant inverse correlation between

apelin and AVP levels was found within the ASD group (r = -0.61; p =

0.007), but not in healthy participants (r = ?0.26; p = 0.25).

Multivariate linear regression analysis showed that only AVP

concentrations independently predicted apelin values in ASD individuals

(? = ?0.42, t = 2.63, p = 0.014). No correlation was seen between apelin

levels and CARS scores (r = ?0.10; p = 0.68).

Conclusions

Our findings of a significantly reduced peripheral level of apelin

coupled with elevated AVP point to a subtle but definite

vasopressinergic dysfunction in autism that could play a role in the

etiopathophysiology of this disorder in humans.

Key Words: Autistic spectrum disorders; Neuropeptides; Vasopressin; Apelin

Address reprint requests to: Dr. Enzo Emanuele, Interdepartment Center

for Research in Molecular Medicine (CIRMC), University of Pavia, Viale

Taramelli, 24, I-27100 Pavia, Italy

1 These authors contributed equally to this work.