Serum Matrix Metalloproteinases and Left Atrial Remodeling-The Hoorn Study

Identification of Circulating Plasma Proteins as a Mediator of Hypertension-Driven Cardiac Remodeling: A Mediation Mendelian Randomization Study

BACKGROUND

This study focused on circulating plasma protein profiles to identify mediators of hypertension-driven myocardial remodeling and heart failure.

METHODS

A Mendelian randomization design was used to investigate the causal impact of systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure on 82 cardiac magnetic resonance traits and heart failure risk. Mediation analyses were also conducted to identify potential plasma proteins mediating these effects.

RESULTS

Genetically proxied higher SBP, DBP, and pulse pressure were causally associated with increased left ventricular myocardial mass and alterations in global myocardial wall thickness at end diastole. Elevated SBP and DBP were linked to increased regional myocardial radial strain of the left ventricle (basal anterior, mid, and apical walls), while higher SBP was associated with reduced circumferential strain in specific left ventricular segments (apical, mid-anteroseptal, mid-inferoseptal, and mid-inferolateral walls). Specific plasma proteins mediated the impact of blood pressure on cardiac remodeling, with FGF5 (fibroblast growth factor 5) contributing 2.96% (P=0.024) and 4.15% (P=0.046) to the total effect of SBP and DBP on myocardial wall thickness at end diastole in the apical anterior segment and leptin explaining 15.21% (P=0.042) and 23.24% (P=0.022) of the total effect of SBP and DBP on radial strain in the mid-anteroseptal segment. Additionally, FGF5 was the only mediator, explaining 4.19% (P=0.013) and 4.54% (P=0.032) of the total effect of SBP and DBP on heart failure susceptibility.

CONCLUSIONS

This mediation Mendelian randomization study provides evidence supporting specific circulating plasma proteins as mediators of hypertension-driven cardiac remodeling and heart failure.

Remodeling and Fibrosis of the Cardiac Muscle in the Course of Obesity-Pathogenesis and Involvement of the Extracellular Matrix

Obesity is a growing epidemiological problem, as two-thirds of the adult population are carrying excess weight. It is a risk factor for the development of cardiovascular diseases (hypertension, ischemic heart disease, myocardial infarct, and atrial fibrillation). It has also been shown that chronic obesity in people may be a cause for the development of heart failure with preserved ejection fraction (HFpEF), whose components include cellular hypertrophy, left ventricular diastolic dysfunction, and increased extracellular collagen deposition. Several animal models with induced obesity, via the administration of a high-fat diet, also developed increased heart fibrosis as a result of extracellular collagen accumulation. Excessive collagen deposition in the extracellular matrix (ECM) in the course of obesity may increase the stiffness of the myocardium and thereby deteriorate the heart diastolic function and facilitate the occurrence of HFpEF. In this review, we include a rationale for that process, including a discussion about possible putative factors (such as increased renin–angiotensin–aldosterone activity, sympathetic overdrive, hemodynamic alterations, hypoadiponectinemia, hyperleptinemia, and concomitant heart diseases). To address the topic clearly, we include a description of the fundamentals of ECM turnover, as well as a summary of studies assessing collagen deposition in obese individuals.

Levels of Serum sST2, MMP-3, and Gal-3 in Patients with Essential Hypertension and Their Correlation with Left Ventricular Hypertrophy

Essential hypertension (EH) is a clinically frequent cardiovascular disease, with insidious onset, causing increased pressure load and neuroregulation disorders in patients. Long-term EH can cause left ventricular hypertrophy (LVH), which can lead to arrhythmia and even death. The soluble suppression of tumorigenicity 2 (sST2), matrix metalloproteinase-3 (MMP-3), and galectin-3 (Gal-3) in serum plays an important role in the occurrence, development, and prognosis of cardiovascular diseases. In our study, we divided EH patients into 3 levels and groups with or without LVH, according to their condition. The levels of sST2, MMP-3, and Gal-3 in the serum were measured in different groups of patients. Our results showed that the levels of sST2, MMP-3, and Gal-3 in the serum increased progressively with the level in different EH groups. The levels of sST2, MMP-3, and Gal-3 in the serum of the LVH group were higher than those of the NLVH group, and it is positively correlated with LVH-related indexes. The risk of developing and progressing to LVH in patients with EH can be determined by the method of measuring three indicators.

Different circulating biomarkers in women and men with paroxysmal atrial fibrillation: results from the AF-RISK and RACE V studies

Aims

The clinical risk profile of atrial fibrillation (AF) patients is different in men and women. Our aim was to identify sex differences in blood biomarkers in patients with paroxysmal AF.

Methods and results

Sex differences in 92 blood biomarkers were measured in 364 patients included in our discovery cohort, the identification of a risk profile to guide atrial fibrillation therapy (AF-RISK) study, assessed by multivariable logistic regression and enrichment pathway analysis. Findings were subsequently confirmed in 213 patients included in our validation cohort, the Reappraisal of Atrial Fibrillation: Interaction between HyperCoagulability, Electrical remodelling, and Vascular Destabilisation in the Progression of AF (RACE V) study. In the discovery cohort, mean age was 59 ± 12 years, 41% were women. CHA₂DS₂-VASc-score was 1.6 ± 1.4. A total of 46% had hypertension, 10% diabetes, and 50% had heart failure, predominantly with preserved ejection fraction (47%). In women, activated leucocyte cell adhesion molecule (ALCAM) and fatty acid binding protein-4 (FABP-4) were higher. In men, matrix metalloproteinase-3 (MMP-3), C-C motif chemokine-16 (CCL-16), and myoglobin were higher. In the validation cohort, four out of five biomarkers could be confirmed: levels of ALCAM (P = 1.73 × 10^–4) and FABP-4 (P = 2.46 × 10^–7) and adhesion biological pathways [false discovery rate (FDR) = 1.23 × 10^–8] were higher in women. In men, levels of MMP-3 (P = 4.31 × 10^–8) and myoglobin (P = 2.10 × 10^–4) and markers for extracellular matrix degradation biological pathways (FDR = 3.59 × 10^–9) were higher.

Conclusion

In women with paroxysmal AF, inflammatory biomarkers were more often higher, while in men with paroxysmal AF, biomarkers for vascular remodelling were higher. Our data support the clinical notion that pathophysiological mechanisms in women and men with AF may differ.

Trial registration

Clinicaltrials.gov identifier NCT01510210 for AF-RISK; Clinicaltrials.gov NCT02726698 for RACE V.

EphA4 is highly expressed in the atria of heart and its deletion leads to atrial hypertrophy and electrocardiographic abnormalities in rats

AIMS

EphA4 is a member of the Eph receptor family, and expressed mainly in central nervous system (CNS), which is involved in CNS development and multiple diseases. Due to the variability in EphA4 expression, we wondered if EphA4 is expressed in other tissues, and what role does EphA4 play?

MATERIALS AND METHODS

We generated an EphA4 knockout (KO) rat line with red fluorescent marker protein encoded by the mCherry cassette inserted downstream of the EphA4 promoter as a reporter. Using this system, we observed high expression of EphA4 in the heart atria and in the brain.

KEY FINDINGS

EphaA4 KO rats (EphA4^-/-) developed obvious atrial hypertrophy with an increased atria-to-heart weight ratio and atrial cardiomyocyte cross-sectional area at six months of age. EphA4^-/- rats had reduced atrial end diastolic volume (EDV), atrial ejection fraction (EF) and left ventricular EF. They also exhibited increased amplitude of QRS complexes and QT intervals, with invisible p waves. RNA sequencing revealed that EphA4 KO altered the transcription of multiple genes involved in regulation of transcription and translation, ion binding, metabolism and cell adhesion. Deletion of EphA4 reduced IGF1 mRNA and protein expression, which is involved in cardiac remodeling.

SIGNIFICANCE

Our data demonstrated that EphA4 was highly expressed in the atria and its deletion caused atrial dysfunction. Our findings also suggested that the EphA4 KO rat could be a potential model for studies on atrial remodeling.

[Change of serum levels of pentraxin-3 and syndecan-4 in children with chronic heart failure]

OBJECTIVE

To study the change and significance of serum pentraxin-3 (PTX-3) and syndecan-4 in children with chronic heart failure (CHF).

METHODS

A total of 40 children with CHF who were admitted to the Department of Pediatrics of the First Affiliated Hospital of Zhengzhou University were enrolled as the heart failure group, and 30 children who underwent physical examination in the outpatient service during the same period of time were enrolled as the control group. The serum levels of PTX-3, syndecan-4, and N-terminal pro-brain natriuretic peptide (NT-proBNP) were compared between the two groups.

RESULTS

The children with CHF had significant reductions in the serum levels of PTX-3, syndecan-4, and NT-proBNP after treatment. The levels of these markers in children with CHF were significantly higher than the control group before and after treatment (P < 0.05). The CHF children with grade II/III/IV cardiac function had significantly higher serum levels of PTX-3 and syndecan-4 than the control group (P < 0.05). The levels of PTX-3 and syndecan-4 were related to the severity of cardiac function. Compared with the grade II cardiac function group, the grade IV cardiac function group had significant increases in the serum levels of PTX-3 and syndecan-4 (P < 0.05). The serum level of PTX-3 was positively correlated with that of syndecan-4 in children with CHF (r_s=0.999, P < 0.05); the serum level of PTX-3 was positively correlated with NT-proBNP, left ventricular mass index (LVMI), and cardiac function grade (r_s=0.726, 0.736, and 0.934 respectively, P < 0.05) and was negatively correlated with left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) (r_s=-0.852 and -0.767 respectively, P < 0.05); the serum level of syndecan-4 was positively correlated with NT-proBNP, LVMI, and cardiac function grade (r_s=0.733, 0.743, and 0.934 respectively, P < 0.05) and was negatively correlated with LVEF and LVFS (r_s=-0.856 and -0.771 respectively, P < 0.05).

CONCLUSIONS

Serum PTX-3 and syndecan-4 may be involved in the development and progression of ventricular remodeling in children with CHF and may be used as markers for the diagnosis, cardiac function grading, and treatment outcome evaluation of children with heart failure.