A combined bioinformatics, experimental and clinical approach to identify novel cardiac-specific heart failure biomarkers: is Dickkopf-3 (DKK3) a possible candidate?

Association of Urinary Dickkopf-3 Levels with Cardiovascular Events and Kidney Disease Progression in Systolic Blood Pressure Intervention Trial

Key Points

In unadjusted analyses, elevated urinary Dickkopf-3 levels were strongly associated with higher risks of cardiovascular disease, ESKD, AKI, and mortality. However, associations were substantially weakened after adjustment for eGFR and albuminuria, suggesting limited prognostic value.

Background

Urinary Dickkopf-3 (uDKK3) is a tubular epithelial-derived profibrotic protein secreted into the urine under tubular stress. It is associated with kidney disease progression in persons with CKD and diabetes and postoperative and contrast-associated AKI. We explored associations of uDKK3 with cardiovascular disease (CVD), kidney, and mortality outcomes within the subset of Systolic Blood Pressure Intervention Trial participants with nondiabetic CKD.

Methods

We included 2344 participants with eGFR <60 ml/min per 1.73 m2 at baseline. We used Cox proportional hazards models to evaluate associations of uDKK3 with CVD (acute decompensated heart failure, myocardial infarction, acute coronary syndrome, stroke, or CVD death), kidney outcomes (incident ESKD, incident AKI, and eGFR decline ≥30%), and all-cause mortality. We used linear mixed models to examine the association of uDKK3 with annual percentage change in eGFR. Models were adjusted for demographic and clinical characteristics, eGFR, and albuminuria.

Results

Over a median follow-up of 3.5 years, there were 292 CVD, 73 ESKD, 183 AKI, 471 eGFR decline, and 228 mortality events. In multivariable models without adjustment for eGFR and albuminuria, uDKK3 was strongly associated with CVD, ESKD, AKI, eGFR decline ≥30%, and mortality. However, after further adjustment for eGFR and albuminuria, uDKK3 was no longer associated with risks for composite CVD (hazard ratio, 1.07; 95% confidence interval, 0.92 to 1.23), ESKD (0.80; 0.62 to 1.02), AKI (1.01; 0.85 to 1.21), eGFR decline ≥30% (0.88; 0.79 to 0.99), or mortality (1.02; 0.87 to 1.20). For the linear eGFR change outcome, higher uDKK3 also had no association in the fully adjusted model (−0.03; −0.41 to 0.36).

Conclusions

Among individuals with hypertension and nondiabetic CKD, higher uDKK3 appeared to have associations with a greater risk of CVD events, incident ESKD, incident AKI, eGFR decline ≥30%, and mortality but these associations were not independent of eGFR and albuminuria.

Blood-Based Biomarkers to Search for Atrial Fibrillation in High-Risk Asymptomatic Individuals and Cryptogenic Stroke Patients

Background

Atrial fibrillation (AF) increases the risk of ischemic stroke in asymptomatic individuals and may be the underlying cause of many cryptogenic strokes. We aimed to test the usefulness of candidate blood-biomarkers related to AF pathophysiology in two prospective cohorts representative of those populations.

Methods

Two hundred seventy-four subjects aged 65–75 years with hypertension and diabetes from the AFRICAT cohort, and 218 cryptogenic stroke patients aged >55 years from the CRYPTO-AF cohort were analyzed. AF was assessed by 4 weeks of monitoring with a wearable Holter device (NuuboTM™). Blood was collected immediately before monitoring started. 10 candidate biomarkers were measured by automated immunoassays (Roche, Penzberg) in the plasma of all patients. Univariate and logistic regression analyses were performed in each cohort separately.

Results

Atrial fibrillation detection rate was 12.4% (AFRICAT cohort) and 22.9% (CRYPTO-AF cohort). 4 biomarkers were significantly increased in asymptomatic individuals with AF [Troponin-T, Angiopoietin-2 (Ang-2), Endocan, and total N-terminal pro-B type natriuretic peptide (NT-proBNP)] and 7 biomarkers showed significantly higher concentrations in cryptogenic stroke patients with AF detection [growth differentiation factor 15, interleukin 6, Troponin-T, Ang-2, Bone morphogenic protein 10, Dickkopf-related protein 3 (DKK-3), and total NT-proBNP]. The models including Ang-2 and total NT-proBNP [AUC 0.764 (0.665–0.863)], and Ang-2 and DKK-3 [AUC = 0.733 (0.654–0.813)], together with age and sex, showed the best performance to detect AF in high-risk asymptomatic individuals, and in cryptogenic stroke patients, respectively.

Conclusion

Blood-biomarkers, in particular, total NT-proBNP, DKK-3, and Ang-2, were associated with AF reflecting two mechanistically different pathways involved in AF pathophysiology (AF stretch and vascular changes). The combination of these biomarkers could be useful in AF screening strategies in the primary care setting and also for searching AF after cryptogenic stroke.

Dickkopf Homolog 3 (DKK3) as a Prognostic Marker in Lupus Nephritis: A Prospective Monocentric Experience

Background: The gold standard for diagnosis of lupus nephritis (LN) is still represented by renal biopsy, and serological prognostic biomarkers are still lacking. Dickkopf homolog-3 (DKK3) has been suggested as a marker of tissue fibrosis in different conditions; however, its role in autoimmune diseases needs to be elucidated. Here, we investigated the prognostic role of DKK3 in systemic lupus erythematosus (SLE) patients with and without LN, assessing its changes in relation to kidney function, flares, and interstitial fibrosis. Methods: Overall, 132 SLE patients (57 with LN) were included and prospectively followed up for at least 36 months. DKK3 was measured in serum at baseline. Biopsies were evaluated for glomerular involvement, interstitial fibrosis, and tubular atrophy. Results: Patients with biopsy-proven LN had significantly higher levels of DKK3 than those without (median [min−max]: 215 ng/mL [81−341] vs. 21.1 ng/mL [1−69], p < 0.01). DKK3 levels were associated with prevalent chronic kidney diseases (OR: 4.31 [C.I. 2.01−6.61] per DKK3 doubling, p < 0.01), higher chronicity index at biopsy (1.75 [1.51−2.77] per DKK3 doubling, p < 0.01), and flares rate (OR: 1.45 [C.I. 1.1−5.71] per DKK3 doubling, p < 0.044). Conclusions: While kidney biopsy still represents the gold standard for diagnostic and prognostic assessment in LN, DKK3 could represent an additional prognostic tool to monitor SLE patients and guide therapeutic choices.

A New Biomarker Tool for Risk Stratification in “de novo” Acute Heart Failure (OROME)

Background: Inflammation is one of the mechanisms involved in heart failure (HF) pathophysiology. Thus, the acute phase reactant protein, orosomucoid, was associated with a worse post-discharge prognosis in de novo acute HF (AHF). However, the presence of anti-inflammatory adipokine, omentin, might protect and reduce the severity of the disease. We wanted to evaluate the value of omentin and orosomucoid combination for stratifying the risk of these patients.

Methods and Results: Two independent cohorts of patients admitted for de novo AHF in two centers were included in the study (n = 218). Orosomucoid and omentin circulating levels were determined by ELISA at discharge. Patients were followed-up for 317 (3–575) days. A predictive model was determined for the primary endpoint, death, and/or HF readmission. Differences in survival were evaluated using a Log-rank test. According to cut-off values of orosomucoid and omentin, patients were classified as UpDown (high orosomucoid and low omentin levels), equal (both proteins high or low), and DownUp (low orosomucoid and high omentin levels). The Kaplan Meier determined a worse prognosis for the UpDown group (Long-rank test p = 0.02). The predictive model that includes the combination of orosomucoid and omentin groups (OROME) + NT-proBNP values achieved a higher C-index = 0.84 than the predictive model with NT-proBNP (C-index = 0.80) or OROME (C-index = 0.79) or orosomucoid alone (C-index = 0.80).

Conclusion: The orosomucoid and omentin determination stratifies de novo AHF patients into the high, mild, and low risk of rehospitalization and/or death for HF. Its combination with NT-proBNP improves its predictive value in this group of patients.

The emerging plasma biomarker Dickkopf-3 (DKK3) and its association with renal and cardiovascular disease in the general population

Dickkopf-3 (DKK3) is an emerging biomarker for cardiovascular disease (CVD) and chronic kidney disease (CKD). Herein, baseline DKK3 plasma levels were measured in 8420 subjects from the Prevention of Renal and Vascular ENd-stage Disease (PREVEND) cohort, a large general population cohort, using enzyme-linked immunosorbent assays. Associations with clinical variables and outcomes were analysed. Median DKK3 level was 32.8 ng/ml (28.0–39.0). In multivariable linear regression analysis, the strongest correlates for plasma DKK3 were age, body mass index and estimated glomerular filtration rate (eGFR). At baseline, 564 (6.7%) subjects had CVD (defined as a myocardial infarction and/or cerebrovascular accident) and 1361 (16.2%) subjects had CKD (defined as eGFR < 60 ml/min/1.73m² and/or urinary albumin excretion (UAE) > 30 mg/24 h). Of subjects with known CVD and CKD follow-up status (respectively 7828 and 5548), 669 (8.5%) developed CVD and 951 (17.1%) developed CKD (median follow-up respectively 12.5 and 10.2 years). Crude logistic regression analysis revealed that DKK3 levels were associated with prevalent CVD (Odds ratio: 2.14 [1.76–2.61] per DKK3 doubling, P < 0.001) and CKD (Odds ratio: 1.84 [1.59–2.13] per DKK3 doubling, P < 0.001). In crude Cox proportional hazard regression analysis, higher DKK3 levels were associated with higher risk for new-onset CVD (Hazard ratio: 1.47 [1.13–1.91] per DKK3 doubling, P = 0.004) and CKD (Hazard ratio: 1.45, [1.25–1.69] per DKK3 doubling, P < 0.001). However, these associations remained no longer significant after correction for common clinical variables and risk factors, though independently predicted for new-onset CKD in a subgroup of subjects with the lowest UAE values. Together, DKK3 plasma levels are associated with cardiovascular risk factors, but are generally not independently associated with prevalent and new-onset CVD and CKD and only predicted for new-onset CKD in those subjects with the lowest UAE values.

The Time Has Come to Explore Plasma Biomarkers in Genetic Cardiomyopathies

For patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) or arrhythmogenic cardiomyopathy (ACM), screening for pathogenic variants has become standard clinical practice. Genetic cascade screening also allows the identification of relatives that carry the same mutation as the proband, but disease onset and severity in mutation carriers often remains uncertain. Early detection of disease onset may allow timely treatment before irreversible changes are present. Although plasma biomarkers may aid in the prediction of disease onset, monitoring relies predominantly on identifying early clinical symptoms, on imaging techniques like echocardiography (Echo) and cardiac magnetic resonance imaging (CMR), and on (ambulatory) electrocardiography (electrocardiograms (ECGs)). In contrast to most other cardiac diseases, which are explained by a combination of risk factors and comorbidities, genetic cardiomyopathies have a clear primary genetically defined cardiac background. Cardiomyopathy cohorts could therefore have excellent value in biomarker studies and in distinguishing biomarkers related to the primary cardiac disease from those related to extracardiac, secondary organ dysfunction. Despite this advantage, biomarker investigations in cardiomyopathies are still limited, most likely due to the limited number of carriers in the past. Here, we discuss not only the potential use of established plasma biomarkers, including natriuretic peptides and troponins, but also the use of novel biomarkers, such as cardiac autoantibodies in genetic cardiomyopathy, and discuss how we can gauge biomarker studies in cardiomyopathy cohorts for heart failure at large.

MicroRNA‑138‑5p drives the progression of heart failure via inhibiting sirtuin 1 signaling

The present study aimed to investigate the regulatory effects of microRNA-138-5p (miR-138-5p) and sirtuin 1 (SIRT1) on the progression of heart failure (HF). The binding association between miR-138-5p and SIRT1 was assessed by the dual-luciferase reporter assay. By conducting reverse transcription-quantitative polymerase chain reaction and Western blotting, relative levels of SIRT1 and p53 regulated by miR-138-5p were detected. In vitro HF models were generated by hydrogen peroxide (H₂O₂) induction in AC-16 and human cardiomyocyte (HCM) cells, followed by detection of the regulatory effects of SIRT1 on cell apoptosis and p53 expression. MiR-138-5p was negatively correlated with the SIRT1 level in cardiomyocytes. By recognizing and specifically targeting SIRT1 3′-untranslated region (3′-UTR), miR-138-5p decreased the translational level of SIRT1 and inhibited its enzyme activity, thereby decreasing the deacetylation level of p53. Through downregulating SIRT1 and activating p53 signaling, miR-138-5p induced apoptosis in H₂O₂-induced AC-16 and HCM cells. By contrast, knockdown of miR-138-5p in the in vitro HF models significantly protected the cardiomyocytes. SIRT1 contributed toward alleviate HF by inhibiting cardiomyocyte apoptosis via enhancing the deacetylation level of p53. MiR-138-5p decreases the enzyme activity of SIRT1 by specifically targeting its 3′-UTR and activates p53 signaling, followed by triggering cardiomyocyte apoptosis during the process of HF. It is considered that miR-138-5p and SIRT1 may be potential diagnostic biomarkers and therapeutic targets for HF.