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ORIGINAL INVESTIGATION
Decreased whole-blood global DNA methylation is related to serum
hormones in anorexia nervosa adolescents
L. TREMOLIZZO
1
*
, E. CONTI
1
*
, M. BOMBA
2
, O. UCCELLINI
2
, M.S. ROSSI
2
,
M. MARFONE
2
, F. CORBETTA
2
, M.E. SANTARONE
1
, M.E. RAGGI
3
, F. NERI
2
,
C. FERRARESE
1
& R. NACINOVICH
2
1
Department of Neurology,
2
Department of Child Neuropsychiatry, San Gerardo Hospital, Monza and University of
Milano-Bicocca, Monza, Italy, and
3
Clinical Analysis Laboratory, “Eugenio Medea” Scientific Institute, Bosisio Parini
(LC), Italy
Abstract
Objectives. The one-carbon metabolism, also known as methionine-homocysteine cycle, governs the dynamics of DNA
methylation, epigenetically regulating gene expression, and has been reported altered in anorexia nervosa (AN) adult
patients. The aim of this study consisted in assessing whole-blood DNA methylation in adolescent AN patients, assessing
its significance in relationship to clinical and hormonal variables. Methods. Whole-blood global DNA methylation was
measured as incorporation of [
3
H]dCTP following HpaII cut in 32 adolescent females affected by restrictive type AN and
compared to 13 healthy controls. Homocysteine, vitamin B
12
and folate plasma levels were assessed as well as fasting plasma
levels of leptin and steroid hormones. Clinical variables, including severity and associate states and traits, were assessed by
means of the EDI-3, CDI and STAI-Y scales. Results. We confirm that whole-blood global DNA methylation is modestly
albeit significantly reduced in AN adolescents with respect to controls, correlating with plasma leptin and steroid hormone
levels. Conversely, clinical traits did not correlate with the outcome variable. Conclusions. A better definition of the epigenetic
dysregulation underlying AN pathology or vulnerability might lead to develop useful markers for diagnosis, prognostic
classification and tailored therapeutic interventions in these vulnerable patients since the earliest phases of their disease.
Key words: anorexia nervosa, DNA methylation, whole blood, biomarkers, epigenetics
Introduction
Anorexia nervosa (AN) is a complex neuropsychiat-
ric eating disorder strictly associated to brain circuit
dysfunctions that still need to be fully elucidated
(Hay and Sachdev 2011). This disrupted neurocir-
cuitry in AN conceivably underlies major synaptic
rearrangements during adolescence or pre-adolescence,
a critical period for the maturing brain, when pivotal
changes take place driven by hormonal, physical
and socio-environmental strictly intertwined forces
(Krassas 2003; Blakemore et al. 2010). Epigenetic
modifications of DNA and chromatin histones clearly
represent one major brain function determinant at
the interface of the gene–environment interaction
both during the ontogenesis and in adulthood, as
previously shown in the setting of other neuropsychi-
atric conditions and treatments (Tremolizzo et al.
2002, 2013a; Weaver et al. 2004). Among environ-
mental modifiers of the epigenoma, diet certainly
plays a major role, further strengthening the link
with cancer, the prototypical epigenetic disease
among other complex disorders (Parle-McDermott
and Ozaki 2011; Kaelin and McKnight 2013).
Specifically, maternal diet has been repeatedly shown
in animal models to influence the epigenetic pattern
in the offspring (Waterland et al. 2006), determining
various adult phenotypes of disease (Sinclair et al.
2007). Human studies also have shown demethyla-
tion at the imprinted insulin-like growth factor 2
( IGF2) locus associated to higher fat density and
*
These authors equally contributed to the work.
Correspondence: Lucio Tremolizzo, MD, PhD, Section of Neurology, DCMT, University of Milano-Bicocca, S. Gerardo Hospital, via
Pergolesi 33, 20900 Monza (MI), Italy. Tel: 39 2 6448 8128. Fax: 39 2 6448 8108. E-mail: lucio.tremolizzo@unimib.it
(Received 22 July 2013; accepted 21 October 2013)
The World Journal of Biological Psychiatry, 2013; Early Online: 1–7
ISSN 1562-2975 print/ISSN 1814-1412 online © 2013 Informa Healthcare
DOI: 10.3109/15622975.2013.860467