AMERICAN JOURNAL OF HYPERTENSION 1
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Arterial stiffening is the predominant abnormal symptom in
isolated systolic hypertension (ISH). The factors that cause
arterial stiffening are likely to be involved in the development
of ISH, which was therein reported.1 The main physiological
identification stiffness of large artery includes structural com-
ponents of the arterial wall, smooth muscle tone, and mean
arterial pressure.2 Elastin (ELN), of the various structural pro-
teins, is the major source of arteries’ “elastic” properties.
In many patients with ISH, the arterial wall contains
decreased amounts of extracellular matrix proteins.3,4 ELN
is an important structural protein of the extracellular matrix
and is mainly confined to the internal elastic lamina in large
arteries. An ELN gene has been located on chromosome 7 in
humans.5 Several polymorphisms of the ELN gene have been
described.6,7 For example, deletion involving 7q11.23 that
results in hemizygosity of the ELN gene has been identified
as the mechanism responsible for the Williams and Buren
syndrome,8 which is characterized by supravalvular aortic
stenosis, hypertension, or peripheral stenoses. Hanon et al.
identified the relationship between the Ser422Gly polymor-
phism of the ELN gene in exon 16 (rs2071307) and the disten-
sibility of elastic arteries.9 Interestingly, Iwai et al. revealed the
association of the rs34208922 polymorphism with hyperten-
sion and pulse wave velocity (PWV).10 Furthermore, Akagawa
et al. reported that single-nucleotide polymorphism (SNP)
(rs34208922) is involved in the reduction of ELN mRNA
transcripts in vitro and ex vivo.11 Recently, ELN has also been
suggested to be a potential candidate gene for familial intrac-
ranial aneurysms12,13 and subarachnoid hemorrhages,14
which we also found defects in the internal elastic lamina.
As a result, ELN may be considered as a functional candidate
gene for ISH.
PWV is a known marker of arterial stiffness and defined as
the speed in which the pulse wave travels along the length of an
artery.15 In Chinese patients with essential hypertension (EH),
it was reported that at any given systolic blood pressure (SBP),
brachial–ankle PWV (baPWV) decreased with the increasing
diastolic blood pressure (DBP), and at any given DBP, baPWV
increased with the increasing SBP.16 In addition, baPWV was
higher in patients with ISH compared to age-matched healthy
individuals.4 Serum C-reactive protein (CRP) is known as
a marker of inflammation and some studies have shown that
inflammation is independently associated with arterial stiffness
and PWV. Alternatively, inflammation may induce structural
1Department of Cardiology, Nanfang Hospital, Southern Medical University,
Guangzhou, China; 2Key Laboratory of Organ Failure, Ministry of Education,
China; 3Department of Gerontal Cardiology, People’s Hospital of Xinjiang
Uygur Autonomous Region, Urumqi, China; 4Department of Neurology,
Center Hospital of Zhanjiang, Zhanjiang, China. Correspondence: Ding-Li Xu
Received 11 September 2008; first decision 6 October 2008; accepted 19 February
2009; advance online publication 00 Month 2009. doi:10.1038/ajh.2009.53
© 2009 American Journal of Hypertension, Ltd.
A Study on Polymorphisms of Elastin Gene in Chinese
Han Patients With Isolated Systolic Hypertension
Liehua Deng1,2, Rong Huang1–3, Zhanyin Chen4, Lei Wu1,2 and Ding-Li Xu1,2
Elastin (ELN) is mainly located in the internal elastic lamina of large
arteries. Degradation of ELN is expected to induce large vessel
stiffness, which could lead to elderly systolic hypertension. Recent
studies have shown that polymorphism of ELN is associated with
stiffness of elastic arteries and elevated blood pressure; however,
there are no further studies on isolated systolic hypertension (ISH).
We identified the genotype of the ELN gene in 358 patients
with ISH, 413 essential hypertension (EH) patients with elevated
diastolic blood pressure (DBP), and 244 age-matched normotensive
(NT) controls for five single-nucleotide polymorphisms (SNPs)
and detected the brachial–ankle pulse wave velocity (baPWV),
C-reactive protein (CRP), and intima-media thickness (IMT) for
ISH was statistically significant in association with SNP rs34208922
(A allele frequency was 0.068 in ISH patients, 0.036 in EH patients, and
0.014 in NT controls; P < 0.001, Pcorr < 0.005) and possibly with SNP
rs2071307 (A allele frequency was 0.103 in ISH patients, 0.079 in EH
patients, and 0.047 in NT controls; P = 0.002, Pcorr = 0.01), however,
the A allele frequency was not different between ISH patients and EH
patients. In addition, baPWV and CRP were significantly associated
with SNP rs34208922 and rs2071307. The other three SNPs were not
significantly associated with ISH, baPWV, CRP, or IMT. Haplotypes
of TGGTA and TGAT− were also significantly associated with ISH
(P = 0.0001, Pcorr = 0.0021; P = 0.0023, Pcorr = 0.0483).
Variants within the ELN gene are associated with increased risk of ISH
and aortic stiffness in the Chinese Han population.
Am J Hypertens 2009; xx:xxx-xxx © 2009 American Journal of Hypertension, Ltd.
AMERICAN JOURNAL OF HYPERTENSION 7
Polymorphisms of Elastin Gene in Chinese Han Patients
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