Elsevier

Clinical Biochemistry

Volume 61, November 2018, Pages 12-17
Clinical Biochemistry

Autophagy-related 16-like 1gene polymorphism, risk factors for cardiovascular disease and associated carotid intima-media thickness in postmenopausal women

https://doi.org/10.1016/j.clinbiochem.2018.09.006Get rights and content

Highlights

  • ATG16L1 polymorphism is associated with increased carotid intima-media thickness.

  • Polymorphic allele ATG16L1 was found in 77.47% in Brazilian postmenopausal women.

  • Polymorphic identification may be a prognostic strategy for cardiovascular risk.

Abstract

Background

Early identification of asymptomatic postmenopausal women (PW), who are more predisposed to developing cardiovascular disease (CVD), is an important preventive strategy. Autophagy-related 16-like 1 (ATG16L1) is an autophagy gene known to control host immune responses and is associated with a variety of diseases, including CVD.

Objective

The aim of the study was to associate the ATG16L1 polymorphism variant with subclinical carotid atherosclerosis in asymptomatic PW.

Study design

This cross-sectional study included 210 Brazilian postmenopausal women (age ≥ 45 years with amenorrhea ≥12 months). Clinical, anthropometric and biochemical assessments were performed to evaluate the cardiovascular risk factors. DNA was extracted from buccal cells and the ATG16L1 (T300A) polymorphism was determined by the polymerase chain reaction (PCR). The carotid intima-media thickness and/or the presence of plaques were evaluated by carotid duplex ultrasound. For statistical analysis, the t-test, logistic regression and analysis of covariance (ANCOVA) were used.

Results

The presence of the polymorphic allele forATG16L1 (T300A) was found in 77.47% (A/G = 49.87%, G/G = 27.60%). The ATG16L1 (T300A) polymorphism is significantly associated with increased carotid intima-media thickness (IMT) after adjustments of the confounding variables (P < .037). No significant associations were observed between the polymorphism with other risk factors for CVD in PW.

Conclusion

In postmenopausal women, the ATG16L1 (T300A) polymorphism is significantly associated with increased carotid IMT (marker of atherosclerotic disease) after adjustments of the confounding variables (P < .037). Thus, identifying the ATG16L1 polymorphism is an important strategy for screening asymptomatic PW who are more predisposed to developing CVD.

Introduction

In women, aging and menopause are considered cardiovascular risk factors [1] because of estrogen deprivation due to ovarian insufficiency [2]. Coronary heart disease (CHD) is often fatal and over one-half of postmenopausal women (PW) with CHD do not present early symptoms [3]. Therefore, early identification of asymptomatic PW, who are more predisposed to developing CHD, is an important preventive strategy [4]. Detecting early markers enables recognition of subclinical atherosclerotic disease and early intervention in modifiable risk factors [5].

In CHD, conventional risk factors - dyslipidemia, hypertension, diabetes, obesity, smoking - are important [6]. However, individual differences in the immune-genetic profile may modulate the severity of the CHD process [7,8]. The main mechanisms in the installation and development of systemic inflammatory response comprise the complement cascade system, the activation of immune cells by releasing cytokines and the endothelial dysfunction [9]. Studies have shown an immune influence associated with the development of CHD in postmenopausal women by cytokine production and expression of receptors [10,11], heat-shock proteins [12] and genetic polymorphism [13]. The expression of inflammatory molecules is stimulated by risk factors and are under the control of inflammatory cytokines and hemodynamic factors, making its characterization extremely important [14].

Autophagy is an important host defense mechanism, interacting with the innate and acquired immunity to both identify and defend against aggressors [15]. Autophagy is a self-protecting cellular catabolic pathway. At a basal level, autophagy is involved in maintaining normal cellular homeostasis [16,17]. Autophagy is associated with a variety of diseases, including cardiovascular diseases, tumors, neurodegenerative diseases and disorders of the immune system [18,19] in response to environmental stress, such as a sedentary lifestyle, hypoxia or oxidative stress [16,19]. Autophagy-related 16-like 1 (ATG16L1) is an autophagy gene known to control host immune responses [20]. ATG16L1 single nucleotide polymorphism (SNP), rs2241880, encodes a missense variant resulting in a substitution of threonine with alanine at amino acid position 300 (T300A) [20]. The T300A variant is the most prevalent of all ATG16L1 variants, representing approximately 55% of the alleles in the European population and 20–40% of alleles in other populations [20]. A SNP in this gene results in decreased autophagy activity [20]. Evidence shows that autophagy plays an important role in inflammation and inhibition of apoptosis and it has been demonstrated that autophagy plays a protective role in atherosclerosis [21], which acts as a cholesterol efflux promoter [22,23], suggesting that autophagy is a potential mechanism in atherosclerosis [24]. However, there is little evidence regarding the contribution of ATG16L1 polymorphism variants to the regulation of atherosclerosis.

To assess the relationship between autophagy and atherosclerosis, we investigated whether the ATG16L1 polymorphism variant is associated with subclinical carotid atherosclerosis and risk factors in asymptomatic postmenopausal women. This paper presents an association between the ATG16L1 polymorphism and carotid intima-media thickness in the development of atherosclerosis in PW and discusses the theory behind autophagy in the atherosclerosis process.

Section snippets

Study design and sample selection

This is a clinical, analytical and cross-sectional study. The study population was postmenopausal women, aged 45–70 years, seen at the Climacteric and Menopause Outpatient Clinic at the Botucatu Medical School-UNESP, who took part in a study that evaluated clinical and inflammatory markers of subclinical carotid atherosclerosis, which were previously described in detail [25]. Women whose last menstruation was at least 12 months prior to the beginning of the study and aged ≥ 45 years old were

Results

The genotype distributions and allele frequencies for the ATG16L1 polymorphism variant in this population present the dominance was 168 (49.87%) heterozygous (AG), homozygous (AA) with 47 (23.53%) patients and 61 (27.6%) patients with polymorphic homozygote (GG). Note that the allelic frequency of (A) is 262, 47.46% and (G) is 290, 52.54%. Both distributions were in Hardy-Weinberg equilibrium, and there were no differences in the frequency of the homozygous GG polymorphic variant or of the G

Discussion

In this study in an unprecedented way, we have shown that ATG16L1 polymorphism variant is associated with subclinical carotid atherosclerosis in postmenopausal women and that it is important to identify polymorphic targets in women at risk for cardiovascular disease. Many postmenopausal women in urban societies have risk factors for CVD. Detecting conventional risk factors for CVD continues to be important, however new approaches at the immune-inflammatory and molecular levels have shown to be

Conclusion

In conclusion, the ATG16L1 polymorphism variant is associated with subclinical carotid atherosclerosis in postmenopausal women. We have shown that it is important to identify polymorphic targets in postmenopausal women at risk for cardiovascular disease in order to characterize a future adequate prognosis for CHD.

Acknowledgments

The authors thank the Sao Paulo Research Foundation (FAPESP) for financial supported.

Funding

This study was supported by the Sao Paulo Research Foundation (FAPESP), process number 2009/14884-2 and 2009/18256-6. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests

The authors have declared that no competing interests exist.

References (53)

  • M.A. Connelly et al.

    High-density lipoprotein and inflammation in cardiovascular disease

    Transl. Res.

    (2016)
  • M.T. Sorbara et al.

    The protein ATG16L1 suppresses inflammatory cytokines induced by the intracellular sensors Nod1 and Nod2 in an autophagy-independent manner

    Immunity

    (2013)
  • L. Mosca et al.

    Evidence-based guidelines for cardiovascular disease prevention in women: 2007 update

    Circulation

    (2007)
  • P. Collins et al.

    Cardiovascular risk assessment in women - an update

    Climacteric

    (2016)
  • M.I.H. Fonseca et al.

    Impact of menopause and diabetes on atherogenic lipid profile: is it worth to analyse lipoprotein subfractions to assess cardiovascular risk in women?

    Diabetol. Metabol. Syndrome

    (2017)
  • G.L. Burke et al.

    The impact of obesity on cardiovascular disease risk factors and subclinical vascular disease: the Multi-Ethnic Study of Atherosclerosis

    Arch. Intern. Med.

    (2008)
  • A. Gistera et al.

    The immunology of atherosclerosis

    Nat. Rev. Nephrol.

    (2017)
  • F. Abdi et al.

    Effects of hormone replacement therapy on immunological factors in the postmenopausal period

    Climacteric

    (2016)
  • F.N. Bueloni-Dias et al.

    Isolated vitamin D supplementation improves the immune-inflammatory biomarkers in younger postmenopausal women: a randomized, double-blind, placebo-controlled trial

    Menopause

    (2018)
  • E.A. Nahas et al.

    Evaluation of clinical and inflammatory markers of subclinical carotid atherosclerosis in postmenopausal women

    Menopause

    (2014)
  • V.M. Miller et al.

    Genetic polymorphisms associated with carotid artery intima-media thickness and coronary artery calcification in women of the Kronos early Estrogen Prevention Study

    Physiol. Genomics

    (2013)
  • X. Lu et al.

    The role of heat shock protein (HSP) in atherosclerosis: Pathophysiology and clinical opportunities

    Curr. Med. Chem.

    (2010)
  • A. Jayaram et al.

    Autophagy and female genital tract infections: new insights and research directions

    BJOG

    (2014)
  • B. Levine et al.

    Autophagy in immunity and inflammation

    Nature

    (2011)
  • N. Mizushima et al.

    Autophagy fights disease through cellular self-digestion

    Nature

    (2008)
  • A.M. Choi et al.

    Autophagy in human health and disease

    N. Engl. J. Med.

    (2013)
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