Identifying plasma proteomic signatures from health to heart failure, across the ejection fraction spectrum.

Circulating proteins may provide insights into the varying biological mechanisms involved in heart failure (HF) with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF). We aimed to identify specific proteomic patterns for HF, by comparing proteomic profiles across the ejection fraction spectrum. We investigated 4210 circulating proteins in 739 patients with normal (Stage A/Healthy) or elevated (Stage B) filling pressures, HFpEF, or ischemic HFrEF (iHFrEF). We found 2122 differentially expressed proteins between iHFrEF-Stage A/Healthy, 1462 between iHFrEF-HFpEF and 52 between HFpEF-Stage A/Healthy. Of these 52 proteins, 50 were also found in iHFrEF vs. Stage A/Healthy, leaving SLITRK6 and NELL2 expressed in lower levels only in HFpEF. Moreover, 108 proteins, linked to regulation of cell fate commitment, differed only between iHFrEF-HFpEF. Proteomics across the HF spectrum reveals overlap in differentially expressed proteins compared to stage A/Healthy. Multiple proteins are unique for distinguishing iHFrEF from HFpEF, supporting the capacity of proteomics to discern between these conditions.

Temporal evolution of liver function parameters predicts clinical outcome in chronic heart failure patients (Bio-SHiFT study).

BACKGROUND: Liver dysfunction contributes to worse clinical outcomes in heart failure (HF) patients. However, studies exploring temporal evolutions of liver function parameters in chronic HF (CHF) pa- tients, and their associations with clinical outcome, are scarce. Detailed temporal patterns of alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGTP), total bilirubin (TBIL) and albumin (ALB) were investigated, and their relation with clinical outcome, in patients with stable CHF with reduced ejection fraction. METHODS: Tri-monthly plasma samples were collected from 250 patients during 2.2 (1.4-2.5) years of follow-up. ALP, GGTP, ALB, and TBIL were measured in 749 selected samples and the relationship between repeatedly measured biomarker levels and the primary endpoint (PEP; composite of cardiovas- cular death, heart transplantation, left ventricular assist device implantation, and hospitalization for worsened HF) was evaluated by joint models. RESULTS: Mean age was 66 ± 13 years; 74% were men, 25% in New York Heart Association class III-IV. 66 (26%) patients reached the PEP. Repeatedly measured levels of TBIL, ALP, GGTP, and ALB were associated with the PEP after adjustment for N-terminal prohormone B-type natriuretic peptide and high sensitivity troponin T (hazard ratio [95% confidence interval] per doubling of biomarker level: 1.98 [1.32; 2.95], p = 0.002; 1.84 [1.09; 3.05], p = 0.018, 1.33 [1.08; 1.63], p = 0.006 and 1.14 [1.09; 1.20], p < 0.001, respectively). Serial levels of ALP and GGTP, and slopes of the temporal evolutions of ALB and TBIL, adjusted for clinical variables, were also significantly associated with the PEP. CONCLUSIONS: Changes in serum levels of TBIL, ALP, GGTP, and ALB precede adverse cardiovascular events in patients with CHF. These routine liver function parameters may provide additional prognostic information in heart failure with reduced ejection fraction patients in clinical practice.

Genetic Burden of TNNI3K in Diagnostic Testing of Patients With Dilated Cardiomyopathy and Supraventricular Arrhythmias.

BACKGROUND: Genetic variants in TNNI3K (troponin-I interacting kinase) have previously been associated with dilated cardiomyopathy (DCM), cardiac conduction disease, and supraventricular tachycardias. However, the link between TNNI3K variants and these cardiac phenotypes shows a lack of consensus concerning phenotype and protein function. METHODS: We describe a systematic retrospective study of a cohort of patients undergoing genetic testing for cardiac arrhythmias and cardiomyopathy including TNNI3K. We further performed burden testing of TNNI3K in the UK Biobank. For 2 novel TNNI3K variants, we tested cosegregation. TNNI3K kinase function was estimated by TNNI3K autophosphorylation assays. RESULTS: We demonstrate enrichment of rare coding TNNI3K variants in DCM patients in the Amsterdam cohort. In the UK Biobank, we observed an association between TNNI3K missense (but not loss-of-function) variants and DCM and atrial fibrillation. Furthermore, we demonstrate genetic segregation for 2 rare variants, TNNI3K-p.Ile512Thr and TNNI3K-p.His592Tyr, with phenotypes consisting of DCM, cardiac conduction disease, and supraventricular tachycardia, together with increased autophosphorylation. In contrast, TNNI3K-p.Arg556_Asn590del, a likely benign variant, demonstrated depleted autophosphorylation. CONCLUSIONS: Our findings demonstrate an increased burden of rare coding TNNI3K variants in cardiac patients with DCM. Furthermore, we present 2 novel likely pathogenic TNNI3K variants with increased autophosphorylation, suggesting that enhanced autophosphorylation is likely to drive pathogenicity.