Osteopontin predicts clinical outcome in patients after treatment of severe aortic stenosis with transcatheter aortic valve implantation (TAVI)

Novel Biomarkers and Advanced Cardiac Imaging in Aortic Stenosis: Old and New

Currently, the symptomatic status and left ventricular ejection fraction (LVEF) play a crucial role in aortic stenosis (AS) assessment. However, the symptoms are often subjective, and LVEF is not a sensitive marker of left ventricle (LV) decompensation. Over the past years, the cardiac structure and function research on AS has increased due to advanced imaging modalities and potential therapies. New imaging parameters emerged as predictors of disease progression in AS. LV global longitudinal strain has proved useful for risk stratification in asymptomatic severe AS patients with preserved LVEF. The assessment of myocardial fibrosis by cardiac magnetic resonance is the most studied application and offers prognostic information on AS. Moreover, the usage of biomarkers in AS as objective measures of LV decompensation has recently gained more interest. The present review focuses on the transition from compensatory LV hypertrophy (H) to LV dysfunction and the biomarkers associated with myocardial wall stress, fibrosis, and myocyte death. Moreover, we discuss the potential impact of non-invasive imaging parameters for optimizing the timing of aortic valve replacement and provide insight into novel biomarkers for possible prognostic use in AS. However, data from randomized clinical trials are necessary to define their utility in daily practice.

The Role of Biochemical Cardiac Markers in Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Proteins are a component of cardiac biomarkers containing cell structures that are released into the circulation when a myocardial injury occurs. They are essential in the diagnosis, risk assessment, and treatment of patients who have chest pain, are thought to have acute coronary syndrome, or are experiencing acute heart failure exacerbations. There are numerous biochemical cardiac markers, but this article summarizes the basic role of major biochemical cardiac markers, including cardiac natriuretic peptides, cardiac troponins, C-reactive protein (CRP), creatine kinase-MB, heart-type fatty acid-binding protein, ischemia-modified albumin, lipoprotein (a), osteopontin (OPN), and soluble suppression of tumorigenicity 2 (sST2), in AF. Atrial natriuretic peptide may serve as an indicator of atrial integrity, which may help to select appropriate treatment approaches for AF. Higher levels of N-terminal pro-B-type natriuretic peptide and brain natriuretic peptide are predictive of incidental AF. Increased troponin T release may indicate better clinical results following AF ablation. Similarly, CRP increases the risk of the AF-increasing calcium (Ca) influx in atrial myocytes, but not because of atrial fibrosis. Patients with postoperative AF have lower FABP3 gene expression in the atrium. Lipoprotein (a) (Lp[a]) may play a causative role in the onset of AF and impact various cardiac tissues. Clinical trials for Lp(a)-lowering drugs should assess their impact on preventing AF. Also, OPN was highly expressed in the circulation of AF patients and further increased with the progression of AF. sST2 was a reliable predictor of new-onset AF and can improve the accuracy of the AF risk model. There is a greater chance that these cardiac biomarkers might be employed to enhance clinical risk stratification in AF.

Calcific Aortic Valve Stenosis with Aging and Current Development in its Pathophysiology

Aortic stenosis is the most common valvular heart disease affecting the elderly. While most patients have a prolonged asymptomatic phase, the development of symptoms ushers in a phase clinical deterioration that often leads to sudden death without an intervention. Treatment of aortic stenosis with valve replacement often relieves the symptoms but still leaves behind a remodeled left ventricle which may not recover. Understanding the pathophysiology of aortic stenosis and realizing that the disease process may be a more active biological entity rather than a passive degenerative process will help us prevent it. This review serves to summarize the latest literature on the pathophysiology of aortic stenosis in the elderly.

Clinical and Molecular Implications of Osteopontin in Heart Failure

The matricellular protein osteopontin modulates cell-matrix interactions during tissue injury and healing. A complex multidomain structure of osteopontin enables it not only to bind diverse cell receptors but also to interact with various partners, including other extracellular matrix proteins, cytokines, and growth factors. Numerous studies have implicated osteopontin in the development and progression of myocardial remodeling in diverse cardiac diseases. Osteopontin influences myocardial remodeling by regulating extracellular matrix production, the activity of matrix metalloproteinases and various growth factors, inflammatory cell recruitment, myofibroblast differentiation, cardiomyocyte apoptosis, and myocardial vascularization. The exploitation of osteopontin loss- and gain-of-function approaches in rodent models provided an opportunity for assessment of the cell- and disease-specific contribution of osteopontin to myocardial remodeling. In this review, we summarize the recent knowledge on osteopontin regulation and its impact on various cardiac diseases, as well as delineate complex disease- and cell-specific roles of osteopontin in cardiac pathologies. We also discuss the current progress of therapeutics targeting osteopontin that may facilitate the development of a novel strategy for heart failure treatment.

Osteopontin and galectin-3 as biomarkers of maladaptive right ventricular remodeling in pulmonary hypertension

Aim: This study assessed the utility of osteopontin (OPN) and galectin-3 (Gal-3) as biomarkers of maladaptive right ventricular remodeling in pulmonary hypertension (PH). Materials & methods: We examined plasma levels of OPN and Gal-3 in patients with PH (n = 62), dilated cardiomyopathy (n = 34), left ventricular hypertrophy (LVH; n = 47), and controls without right ventricle (RV) or LV abnormalities (n = 38). Results: OPN and Gal-3 levels were higher in PH, dilated cardiomyopathy and LVH than in the controls. OPN concentrations in PH patients with maladaptive RV were significantly higher than in those with adaptive RV. Gal-3 did not differentiate between adaptive and maladaptive RV remodeling in PH. OPN and Gal-3 levels did not correlate with parameters of LV remodeling. Conclusion: OPN is a potential biomarker of RV maladaptation.

Osteopontin and LDLR Are Upregulated in Hearts of Sudden Cardiac Death Victims With Heart Failure With Preserved Ejection Fraction and Diabetes Mellitus

Background: Diabetes mellitus (DM) is associated with increased risk of sudden cardiac death (SCD), particularly in patients with heart failure with preserved ejection fraction (HFpEF). However, there are no known biomarkers in the population with DM and HFpEF to predict SCD risk. Objectives: This study was designed to test the hypothesis that osteopontin (OPN) and some proteins previously correlated with OPN, low-density lipoprotein receptor (LDLR), dynamin 2 (DNM2), fibronectin-1 (FN1), and 2-oxoglutarate dehydrogenase-like (OGDHL), are potential risk markers for SCD, and may reflect modifiable molecular pathways in patients with DM and HFpEF. Methods: Heart tissues were obtained at autopsy from 9 SCD victims with DM and HFpEF and 10 age and gender-matched accidental death control subjects from a Finnish SCD registry and analyzed for the expression of OPN and correlated proteins, including LDLR, DNM2, FN1, and OGDHL by immunohistochemistry. Results: We observed a significant upregulation in the expression of OPN, LDLR, and FN1, and a marked downregulation of DNM2 in heart tissues of SCD victims with DM and HFpEF as compared to control subjects (p < 0.01). Conclusions: The dysregulated protein expression of OPN, LDLR, FN1, and DNM2 in patients with DM and HFpEF who experienced SCD provides novel potential modifiable molecular pathways that may be implicated in the pathogenesis of SCD in these patients. Since secreted OPN and soluble LDLR can be measured in plasma, these results support the value of further prospective studies to assess the predictive value of these plasma biomarkers and to determine whether tuning expression levels of OPN and LDLR alters SCD risk in patients with DM and HFpEF.

The effects of macrophages on cardiomyocyte calcium-handling function using in vitro culture models

Following myocardial infarction (MI), myocardial inflammation plays a crucial role in the pathogenesis of MI injury and macrophages are among the key cells activated during the initial phases of the host response regulating the healing process. While macrophages have emerged as attractive effectors in tissue injury and repair, the contribution of macrophages on cardiac cell function and survival is not fully understood due to complexity of the in vivo inflammatory microenvironment. Understanding the key cells involved and how they communicate with one another is of paramount importance for the development of effective clinical treatments. Here, novel in vitro myocardial inflammation models were developed to examine how both direct and indirect interactions with polarized macrophage subsets present in the post-MI microenvironment affect cardiomyocyte function. The indirect model using conditioned medium from polarized macrophage subsets allowed examination of the effects of macrophage-derived factors on stem cell-derived cardiomyocyte function for up to 3 days. The results from the indirect model demonstrated that pro-inflammatory macrophage-derived factors led to a significant downregulation of cardiac troponin T (cTnT) and sarcoplasmic/endoplasmic reticulum calcium ATPase (Serca2) gene expression. It also demonstrated that inhibition of macrophage-secreted matricellular protein, osteopontin (OPN), led to a significant decrease in cardiomyocyte store-operated calcium entry (SOCE). In the direct model, stem cell-derived cardiomyocytes were co-cultured with polarized macrophage subsets for up to 3 days. It was demonstrated that anti-inflammatory macrophages significantly increased cardiomyocyte Ca²⁺ fractional release while macrophages independent of their subtypes led to significant downregulation of SOCE response in cardiomyocytes. This study describes simplified and controlled in vitro myocardial inflammation models, which allow examination of potential beneficial and deleterious effects of macrophages on cardiomyocytes and vise versa. This can lead to our improved understanding of the inflammatory microenvironment post-MI, otherwise difficult to directly investigate in vivo or by using currently available in vitro models.

Osteopontin as novel biomarker for reversibility of pressure overload induced left ventricular hypertrophy

Aim: The aim of this study was to evaluate the prognostic value of osteopontin (OPN) as a marker for left ventricular (LV) hypertrophy and its reversibility after surgical aortic valve replacement (SAVR). Patients & methods: Echocardiographic data and OPN plasma levels of 149 consecutive patients undergoing SAVR were obtained preoperatively and 3 months postoperatively. OPN was measured by Quantikine Human OPN immunoassay. Results: There was a significant correlation between higher OPN plasma levels and lower LV-mass regression. In patients receiving SAVR combined with coronary artery bypass grafting, high OPN plasma levels were also an indicator for eccentric hypertrophy phenotype. Conclusion: OPN may be a useful indicator for LV hypertrophy phenotype and could have a prognostic value to estimate LV-mass regression after SAVR.

Preoperative frailty parameters as predictors for outcomes after transcatheter aortic valve implantation: a systematic review and meta-analysis

Guidelines suggest using frailty characteristics in the work-up for a transcatheter aortic valve implantation (TAVI). There are many frailty-screening tools with different components. The prognostic value of the individual parameters in frailty is as yet unclear. The objective of this systematic review and meta-analysis was to find and pool predictors for 1‑year mortality after TAVI. We followed a two-step approach. First, we searched for randomised controlled trials on TAVI to identify frailty parameters used in these studies. Second, we searched for publications on these frailty parameters. Articles were included for pooled analysis if the studied frailty parameters were dichotomised with clear cut-off values based on common standards or clinical practice and reported adjusted hazard ratios (HR) of 1‑year mortality after TAVI. We calculated pooled effect estimates of 49 studies based on dichotomised frailty scores (HR: 2.16, 95% CI: 1.57–3.00), chronic lung disease (HR: 1.57, 95% CI: 1.45–1.70), estimated glomerular filtration rate <30 ml/min (HR: 1.95, 95% CI: 1.68–2.29), body mass index <20 kg/m² (HR: 1.49, 95% CI: 1.09–2.03), hypoalbuminaemia (HR: 1.77, 95% CI: 1.38–2.25), anaemia (HR: 2.08, 95% CI: 0.93–4.66), low gait speed (HR: 13.33, 95% CI: 1.75–101.49) and Katz activities of daily living (ADL) score of 1 or more deficits (HR: 5.16, 95% CI: 0.77–34.47). Chronic lung disease, chronic kidney disease, underweight, hypoalbuminaemia, a low frailty score, anaemia, low gait speed and an ADL deficiency were associated with worse 1‑year outcomes after TAVI.

Periprocedural Changes of NT-proBNP Are Associated With Survival After Transcatheter Aortic Valve Implantation

Background

Cardiovascular biomarkers constitute promising tools for improved risk stratification and prediction of outcome in patients undergoing transcatheter aortic valve implantation. We examined the association of periprocedural changes of NT‐proBNP (N‐terminal pro–B‐type natriuretic peptide) with survival after transcatheter aortic valve implantation.

Methods and Results

NT‐proBNP levels were measured in 704 patients before transcatheter aortic valve implantation and at discharge. Patients were grouped as responders and nonresponders depending on an NT‐proBNP–based ratio (postprocedural NT‐proBNP at discharge/preprocedural NT‐proBNP). Overall, 376 of 704 patients showed a postprocedural decrease in NT‐proBNP levels (NT‐proBNP ratio <1). Responders and nonresponders differed significantly regarding median preprocedural (2822 versus 1187 pg/mL, P<0.001) and postprocedural (1258 versus 3009 pg/mL, P<0.001) NT‐proBNP levels. Patients in the nonresponder group showed higher prevalence of atrial fibrillation (47.0% versus 39.4%, P=0.042), arterial hypertension (94.2% versus 87.5%, P=0.002), renal impairment (77.4% versus 69.1%, P=0.013), and peripheral artery disease (24.4% versus 14.6%, P=0.001). In contrast, patients in the responder group had higher prevalence of moderately reduced left ventricular ejection fraction (17.3% versus 11.0%, P=0.017), lower calculated aortic valve area (0.7 versus 0.8 cm², P<0.001), and higher mean pressure gradient (41 versus 35 mm Hg, P<0.001). Median follow‐up was 22.6 months. Kaplan–Meier analysis showed a highly significant survival benefit for the responder group compared with the nonresponder group (log‐rank test, P<0.001).

Conclusions

A ratio based on periprocedural changes of NT‐proBNP is a simple tool for better risk stratification and is associated with survival in patients after transcatheter aortic valve implantation.