Citation: Zhang Y, Cerjak D, Ali O. Finding Epigenetic Determinants of the Metabolic Syndrome. Austin J
Endocrinol Diabetes. 2014;1(6): 1029.
Austin J Endocrinol Diabetes - Volume 1 Issue 6 - 2014
ISSN : 2381-9200 | www.austinpublishinggroup.com
Zhang et al. © All rights are reserved
Austin Journal of Endocrinology and
Diabetes
Open Access
Abstract
Metabolic Syndrome (MetS) substantially increases one’s risk for type 2
diabetes (T2D) and cardiovascular disease. It now affects more than one
third of adults in the U.S. and has similar impact on other societies globally.
Results from recent genome-wide association studies (GWAS) have suggested
that the inherited variance in anindividuals’risk of expressing MetS traits
cannot be completely explained by variation in the primary sequence of the
genome; mechanisms beyond the genetic sequence variants are increasingly
compelling for researchers in the ield. Epigenetic modiications such as DNA
methylation and histone modiications are hypothesized to play important roles
in the pathophysiology of diseases including MetS and may explain some of
the missing heritability. Recent pilot studies conducted in humans and animals
have also suggested epigenetic changes such as CpG methylation modify
one’s susceptibility to developing MetS in response to prenatal and postnatal
environmental exposures. Although these indings are intriguing, more work is
needed in order to unravel a map of epigenetic determinants of MetS.
Keywords: Metabolic Syndrome; DNA Methylation; Epigenetic; Obesity;
Environmental Cues
study population [16]. It is also known that the atherosclerotic process
starts in childhood and is accelerated in individuals who are insulin
resistant, dyslipidemic and/or show signs of systemic inlammation
[17-19]. At a molecular level, the mechanisms by which obesity
leads to the development of insulin resistance, dyslipidemia and
associated phenotypes are poorly understood but necessarily involve
long-term changes in genetic regulation and gene expression. Since
the underlying DNA sequence remains unchanged, these changes
in gene regulation and function must be mediated by epigenetic
mechanisms. hese mechanisms, including methylation of CpG sites
of DNA, are some of the most important processes by which genetic
function is regulated and altered by development and by the external
environment [20-26].
Why study epigenetic in MetS
Epigenetic mechanisms, which involve DNA and histone
modiications, mediate the interaction between gene and environment
throughout the lifespan; while the underlying genetic sequence does
not change, environmental inluences can alter epigenetic marks
and thus alter gene expression and induce long term changes in
phenotype and disease susceptibility [27]. he gradual accumulation
of epigenetic changes in critical genes may contribute to the observed
age-related increase in the prevalence of various chronic disorders
[28-31]. Epigenetic changes are known to be heritable across more
than one generation of ofspring in plants and mammals [32-37]
and there is evidence that transgenerational epigenetic inheritance
also occurs in humans [38-41]. Such transgenerational inheritance
of epigenetic states may contribute to the observed inherited risk of
various chronic disorders, including metabolic disorders [42].
DNA methylation is one of the most extensively studied
epigenetic mechanisms and plays an important role in the process
Introduction
Chronic diseases such as cancer, type 2 diabetes (T2D),
metabolic syndrome (MetS), cardiovascular disease and dementia
constitute the most common health problems seen in developed
societies (increasingly, in developing societies) and their prevalence
increases with age in all populations [1-4]. It is well established that
environmental exposures, especially in early life, can alter the risk of
various chronic diseases later in life [5, 6] and while the mechanisms
involved in this “programming” of future risk are not yet understood
in detail, epigenetic changes are believed to play an important role
in this process [7, 8]. Epigenetic mechanisms are also postulated to
be involved in modifying the risk of MetS secondary to postnatal
exposures and may explain the “missing heritability” of chronic
diseases like MetS. In this mini-review, we discuss the historical
context of the concept of MetS epigenetic, the recent evidence and
our current opinions about this rising ield.
The Metabolic Syndrome
he Metabolic Syndrome (MetS) is a form of obesity characterized
by a cluster of phenotypes that includes increased abdominal fat
mass, impaired insulin responsiveness, dyslipidemia with increased
plasma triglycerides and decreased HDL-cholesterol, increased blood
pressure and elevated circulating cytokines and adipokines [9]. It is
estimated to afect 34% of adult Americans [10] and adds an extra
$2,000 per person in annual health care costs [11]. Its prevalence is
low in childhood and increases with advancing age [12, 13].
he prevalence of MetS-associated cardiovascular (CV) risk
factors is relatively low during early childhood but increases during
adolescence and thereater tends to persist into adulthood [12-15].
We have observed a similar trend in adolescents in our cross-sectional
Mini Review
Finding Epigenetic Determinants of the Metabolic
Syndrome
Zhang Y
1
*, Cerjak D
1
, Ali O
2
1
Department of Medicine, Medical College of Wisconsin,
USA
2
Department of Pediatrics, Medical College of Wisconsin,
USA
*Corresponding author: Zhang Y, Department of
Medicine, Medical College of Wisconsin, USA, Tel: 414-
955-4013; Fax: 414-955-6386; Email: yzhang@mcw.edu
Received: October 03, 2014; Accepted: November 21,
2014; Published: November 27, 2014