Congenital heart disease and coronary atherosclerosis: a looming concern?

Switching of vascular cells towards atherogenesis, and other factors contributing to atherosclerosis: a systematic review

Background

Onset, development and progression of atherosclerosis are complex multistep processes. Many aspects of atherogenesis are not yet properly known. This study investigates the changes in vasculature that contribute to switching of vascular cells towards atherogenesis, focusing mainly on ageing.

Methods

Databases including PubMed, MEDLINE and Google Scholar were searched for published articles without any date restrictions, involving atherogenesis, vascular homeostasis, aging, gene expression, signaling pathways, angiogenesis, vascular development, vascular cell differentiation and maintenance, vascular stem cells, endothelial and vascular smooth muscle cells.

Results

Atherogenesis is a complex multistep process that unfolds in a sequence. It is caused by alterations in: epigenetics and genetics, signaling pathways, cell circuitry, genome stability, heterotypic interactions between multiple cell types and pathologic alterations in vascular microenvironment. Such alterations involve pathological changes in: Shh, Wnt, NOTCH signaling pathways, TGF beta, VEGF, FGF, IGF 1, HGF, AKT/PI3K/ mTOR pathways, EGF, FOXO, CREB, PTEN, several apoptotic pathways, ET - 1, NF-κB, TNF alpha, angiopoietin, EGFR, Bcl - 2, NGF, BDNF, neurotrophins, growth factors, several signaling proteins, MAPK, IFN, TFs, NOs, serum cholesterol, LDL, ephrin, its receptor pathway, HoxA5, Klf3, Klf4, BMPs, TGFs and others.This disruption in vascular homeostasis at cellular, genetic and epigenetic level is involved in switching of the vascular cells towards atherogenesis. All these factors working in pathologic manner, contribute to the development and progression of atherosclerosis.

Conclusion

The development of atherosclerosis involves the switching of gene expression towards pro-atherogenic genes. This happens because of pathologic alterations in vascular homeostasis. When pathologic alterations in epigenetics, genetics, regulatory genes, microenvironment and vascular cell biology accumulate beyond a specific threshold, then the disease begins to express itself phenotypically. The process of biological ageing is one of the most significant factors in this aspect as it is also involved in the decline in homeostasis, maintenance and integrity.The process of atherogenesis unfolds sequentially (step by step) in an interconnected loop of pathologic changes in vascular biology. Such changes are involved in 'switching' of vascular cells towards atherosclerosis.

Substantial Cardiovascular Morbidity in Adults With Lower-Complexity Congenital Heart Disease

BACKGROUND

Although lower-complexity cardiac malformations constitute the majority of adult congenital heart disease (ACHD), the long-term risks of adverse cardiovascular events and relationship with conventional risk factors in this population are poorly understood. We aimed to quantify the risk of adverse cardiovascular events associated with lower-complexity ACHD that is unmeasured by conventional risk factors.

METHODS

A multitiered classification algorithm was used to select individuals with lower-complexity ACHD and individuals without ACHD for comparison among >500 000 British adults in the UK Biobank. ACHD diagnoses were subclassified as isolated aortic valve and noncomplex defects. Time-to-event analyses were conducted for the primary end points of fatal or nonfatal acute coronary syndrome, ischemic stroke, heart failure, and atrial fibrillation and a secondary combined end point for major adverse cardiovascular events. Maximum follow-up time for the study period was 22 years with retrospectively and prospectively collected data from the UK Biobank.

RESULTS

We identified 2006 individuals with lower-complexity ACHD and 497 983 unexposed individuals in the UK Biobank (median age at enrollment, 58 [interquartile range, 51-63] years). Of the ACHD-exposed group, 59% were male, 51% were current or former smokers, 30% were obese, and 69%, 41%, and 7% were diagnosed or treated for hypertension, hyperlipidemia, and diabetes mellitus, respectively. After adjustment for 12 measured cardiovascular risk factors, ACHD remained strongly associated with the primary end points, with hazard ratios ranging from 2.0 (95% CI, 1.5-2.8; P<0.001) for acute coronary syndrome to 13.0 (95% CI, 9.4-18.1; P<0.001) for heart failure. ACHD-exposed individuals with ≤2 cardiovascular risk factors had a 29% age-adjusted incidence rate of major adverse cardiovascular events, in contrast to 13% in individuals without ACHD with ≥5 risk factors.

CONCLUSIONS

Individuals with lower-complexity ACHD had a higher burden of adverse cardiovascular events relative to the general population that was unaccounted for by conventional cardiovascular risk factors. These findings highlight the need for closer surveillance of patients with mild to moderate ACHD and further investigation into management and mechanisms of cardiovascular risk unique to this growing population of high-risk adults.