Abstract
Introduction
Heart failure (HF) is a multifactorial disease, which is the leading cause of morbidity and mortality worldwide. 1 There are various etiologies for HF, such as coronary artery disease, hypertension, valvular heart disease, arrhythmia, dilated cardiomyopathy (DCM), infection and inflammation. Neurohormonal factors play a fundamental role in the pathophysiology of structural changes of the heart (cardiac remodeling), and the subsequently deterioration of cardiac function (heart failure), 2 including activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system, altered expression of endothelin, vascular endothelial growth factor, inflammatory cytokines, pro-oxidant and antioxidant factors, as well as signal transduction components. A number of drugs are available for HF including angiotensin-converting enzyme inhibitors (ACEI), β-blockers, aldosterone antagonists, diuretics and inotropic agents. 3 However, the risk, severity and therapeutic response of HF is variable among individuals, which may be related to genetic variation. 4
The aim of this study was to review the literature for any genetic association with the susceptibility, therapeutic response or prognosis of HF. These findings could then be used to identify risk factors and pharmacogenetic mechanisms of HF, providing information to prevent future cases and to ensure effective therapeutic decisions.
Methods
Literature retrieval
All available articles about HF and gene polymorphisms published between January 1995 and February 2015 were searched for from electronic databases, PubMed, Web of Science and the Chinese National Knowledge Infrastructure (CNKI). The following terms were used as search criteria: ‘heart failure’, ‘HF’, ‘cardiomyopathy’, ‘polymorphism’, ‘variant’, ‘genetic polymorphism’, ‘genetic variant’, ‘susceptibility,’ ‘therapy response’, ‘cardiac remodeling’, ‘severity’, ‘survival’, ‘mortality’, ‘death’, ‘prognosis’ and ‘genetic association study’. Bibliographies in articles provided further references.
Inclusion criteria
Inclusion criteria were defined as: 1) clinical research of cases of HF; 2) publication between January 1995 and February 2015; 3) diagnosis of HF defined: (a) left ventricular ejection fraction (LVEF) ≤45% or abnormal diastolic function and (b) classic HF signs/symptoms, 4) assessment of ≥10 cases; 5) detailed information about morbidity, therapeutic response, and/or prognosis of HF.
Literature analysis
The investigators reviewed data from the published literature independently, and all disagreements were resolved by joint review and consensus.
Results
Genetic polymorphisms and their influence on HF.
12SNPs(HSPB7): rs945416, rs732286, rs1763596, rs1739844, rs1763597, rs1739843, rs1739842, rs1739841, rs1763599, rs761760, rs761759, rs1739840.
HF, heart failure; ACE, angiotensin converting enzyme; AT1R, angiotensin type1 receptor;
AGT, angiotensinogen; SNPs, single nucleotide polymorphisms; ADRB1, β1-adrenergic receptor gene; CTLA, T-lymphocyte antigen; NFKB, nuclear factor kappa B;
Gene polymorphisms and susceptibility to HF
Renin-angiotensin-aldosterone system
Angiotensin converting enzyme (ACE), as a key enzyme catalyzing the production of angiotensin II and the degradation of bradykinin, and plays an important role in the development of HF. A functional intragenic
Angiotensin type1 receptor (AT1R), as the major receptor of angiotensin II, mediates most of the physiologic actions of angiotensin II. Polymorphism
Angiotensinogen (AGT) gene alleles
Sympathetic nervous system
The pivotal role of sympathetic activation in HF and the benefit of anti-adrenergic therapy are well-known.19,20 This study has focused on several functional single nucleotide polymorphisms (SNPs) of the β1-adrenergic receptor gene (
A meta-analysis from Liu,
The β2-adrenergic receptor polymorphism
The α2 c-adrenergic receptor (α2 C-AR) polymorphism
Inflammatory genes
Tumor necrosis factor alpha (TNF-α) is one of the most studied inflammatory cytokines in the pathogenesis of HF. 30 TNF-α causes endothelial dysfunction, muscle contractility reduction and myocardial hypertrophy. 31
A meta-analysis
32
of eight studies demonstrated that the
Cytotoxic T-lymphocyte antigen 4 (CTLA4) is an inhibitory receptor expressed on activated T lymphocytes, which acts as an important negative regulator of T-cell activation. A promoter SNP (
The nuclear factor kappa B family (NF-κB) of transcription factors, major mediators of inflammation, have been implicated in cardioprotection34,35 and in detrimental effects on the heart.36,37 The prevalence of
Mahmoudi,
Endothelial system
The endothelial system plays an important role in the pathogenesis of HF. The endothelin-1 genes (
Vascular endothelial growth factor (VEGF) is a multifunctional protein, inducing receptor-mediated endothelial proliferation, angiogenesis and endothelial integrity. It is involved in microvasculature abnormalities of HF.43,44 Douvaras
Miscellaneous genes
G-protein coupled receptor kinases (GRKs), a large family of receptor-regulating proteins, play pivotal roles in signal transduction of G-protein coupled receptors, especially the β-receptor. The common variant,
Manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, may be induced by increased inflammatory cytokines in cardiomyopathy or myocarditis.
48
Overexpression of MnSOD might protect cardiac cells from damage by these cytokines.
49
A substitution (Val16Ala) might neutralize superoxide radicals in the cells.
50
Homozygosity for
A common intronic variant in heat shock protein (HSP) gene
Micro-RNA sequences
There are several studies focusing on the effects of DNA variants within or adjacent to micro-RNA sequences (miRs). These miRs are short, endogenous, noncoding RNAs that bind to the 3’-untranslated region (3’-UTR) of their target mRNA and regulate the subsequent translation of proteins. MiR-499 u17c was first described in association with human HF, 56 with the c17 mutant misdirecting recruitment of a subset of miR-499 target mRNAs, thus altering steady-state cardiac mRNA and proteins to favorably impact cardiac function. 56 The rs7223247 polymorphism, located within the 3’-UTR of a nonfunctional TLCD2 gene downstream from miR-22 has been implicated in left ventricular hypertrophy (as a strong independent predictor of HF). 57 HCM patients and healthy controls had similar frequencies of the polymorphisms rs45489294 in miRNA 208b and rs13136737 in miRNA 367. 58 However, re998532 in miRNA 1-2, the only variant not detected in the healthy controls, was a rare SNP but not necessarily an HCM-associated mutation. 58
Gene polymorphisms and therapeutic response
Renin-angiotensin-aldosterone system
Several studies have demonstrated that patients with
Sympathetic nervous system
A variety of studies have been performed to evaluate the impact of the β-AR polymorphisms on response to β-blocker therapy. The meta-analysis of Liu,
Magnusson,
For the
Miscellaneous genes
In the general Chinese population,
Cytochrome P4502D6 (CYP2D6) plays an important role in hepatic metabolism, clearing lipophilic β-blocker from the body. CYP2D6 phenotypes are classified as poor metabolizers, intermediate metabolizers, extensive metabolizers and ultrarapid metabolizers.
74
Poor metabolizers have no functional alleles, intermediate metabolizers have two hypofunctional alleles, while ultrarapid and extensive metabolizers have two fully functional alleles.74,75 Previous studies76,77 found no association between
Gene polymorphisms and prognosis of HF
Renin-angiotensin-aldosterone system
Although the
Sympathetic nervous system
From the meta-analysis of Liu,
Several studies aimed to find linkage between the
Inflammatory genes
Tiret,
Endothelial system
Van der Meer,
In the endothelial cell, nitric oxide is synthesized by nitric oxide synthases (NOS). It might exert direct toxic effects on the myocardium and mediate the negative inotropic effects of some inflammatory cytokines.
98
McNamara,
Miscellaneous genes
Adenosine monophosphate deaminase1 (AMPD1) can convert adenosine monophosphate (AMP)
79
to inosine monophosphate (IMP). Changes of
Hua,
Gene-gene interaction
Susceptibility to HF has been demonstrated with the synergistic action of the
Pharmacogenetically, patients who are
Andersson,
Discussion and conclusion
Genetic association studies of HF have been highly controversial; there may be interaction or synergism of several genetic variants which together result in an ultimate pathological phenotype for HF. Understanding the role that genetic variants play in HF development is essential for individualized preventive and therapeutic strategies.
