P5405Clinical and prognostic relevance of increased liver stiffness coupled with abnormal liver function tests in decompensated heart failure

Objective

Recent studies have demonstrated associations of either abnormal liver function tests (LFT) or liver stiffness (LS) increase with negative outcomes in decompensated heart failure (DHF). We aimed to assess incidence, clinical and prognostic relevance of combined increase of LS and LFT in DHF.

Methods

The study included 130 patients (73% male, 68±11 years [M±SD], myocardial infarction 49%, atrial fibrillation 63%, diabetes mellitus 39%, chronic kidney disease 24%, EF 39±14%, EF<40% 54%, NT-proBNP 3601 [1905; 6220] pg/ml, alcohol abuse 26.2%) hospitalized with DHF, in whom levels of alanine transaminase (ALT), aspartate transaminase (AST) and total bilirubin (TB) and LS (using transient elastography) were assessed in the first 48 hours of admission. Patients with previous liver disease or acute hepatitis were excluded. Higher then upper normal limit levels of either AST/ ALT/ TB were considered as LFT increase; LS >5.9 kPa – as abnormal. Outcomes were assessed by phone contacts in 1, 3, 6 and 12 months. Kruskal–Wallis test, Pearson's chi-squared test and Kaplan-Meier survival analysis were used. P<0.05 was considered significant.

Results

Median LS was 11.1 (6.8; 24.5) kPa, median ALT 20.1 (14.9; 30.7) U/l, AST 26 (20; 36.3) U/l, TB 19 (13.2; 27) μmol/l. LS and ALT, AST, TB increase occurred in 79.2 and 15.4, 13.1, 40.8% patients.

Based on combination of LS and LFT increase subjects were divided into 3 groups: without LS and LFT increase (G1, 16.2%), with only LS increase (G2, 33.1%) and both LS and LFT increase (G3, 46.1%). Isolated LFT increase was noted only in 6 (4.6%) patients.

G3 compared to G2 and G1 was characterized by lower EF (33±14 vs 41±13 and 45±11%, p<0.001) and inferior vena cava (IVC) collapsibility (23.3 vs 41.9 and 61.9%, p=0.003), higher IVC diameter (2.4 [2; 2.6] vs 2.2 [2; 2.4] and 2 [1.95; 2.2] cm, p<0.001), right ventricular diameter (3.5 [3.2; 3.9] vs 3.2 [3; 3.6] and 3 [2.9; 3.1] cm, p<0.001), pulmonary artery pressure (56 [45; 66] vs 50 [37; 65] and 40 [33; 49] mmHg, p=0.014), higher rate of tricuspid regurgitation (70 vs 44.2 and 28.6%, p=0.001). Groups did not differ by alcohol abuse rate (p=0.152).

Kaplan–Meier analysis of groups for all-cause death probability showed significant differences (figure): event-free survival for G3 vs G1 and G2 was 64.9 vs 81 and 95% (log rank p=0.011, χ2=6.5 for G3 vs G1; log rank p=0.081, χ2=3.1 for G3 vs G2). HF readmission probability was significantly higher in G3 vs G2 and G1: corresponding event-free survival was 50.9 vs 66.7 and 80% (log rank p=0.012, χ2=6.3 for G3 vs G1; log rank p=0.036, χ2=4.4 for G3 vs G2).

Conclusions

Combination of abnormal LFT and increased LS was observed in 46.1% of DHF patients and was associated with lower EF, more serious right-sided dysfunction and higher probability of negative long-term outcomes.

[Prognostic value of liver stiffness in decompensated heart failure: results of prospective observational transient elastography-based study]

OBJECTIVE

There is growing evidence that liver stiffness (LS) in decompensated heart failure (DHF) is related to congestion, however data about its impact on outcomes are limited. The aim of the study was to evaluate associations and long-term prognostic significance of LS measured by transient elastography (TE) in DHF.

METHODS

Single-center prospective observational study of 194 patients hospitalized with DHF, of whom 71 % were male, 68 ± 11 years (mean ± SD), had a left ventricular ejection fraction of 39±14%. LS by TE (FibroScan 502, Echosens, France) was measured on admission (n=176) and/or discharge (n=165). Outcomes of interest were all-cause death or heart transplantation, heart failure (HF) rehospitalisation, heart valve repair surgery. Outcome analysis was performed with Kaplan-Meier survival curves compared by log-rank test and with Cox proportional hazards regression.

RESULTS

Median LS on admission and discharge were 11.1 (interquartile range 6.3;22.9) and 8.2 (5.8;14.0) kPa, respectively. Higher LS was associated with more clinical congestion on admission and discharge. Patients with LS on admission ≥11.1 kPa and at discharge ≥8.2 kPa were characterised by more pronounced clinical and echocardiographic signs of right-sided HF. Total of 5 (2.6%) patients died in hospital. Further, 31 (17.3%) deaths, 1 (0.6%) heart transplantation, 3 (1.7%) valve repair surgeries and 54 (30.2%) HF rehospitalizations occurred during follow-up (median 183 days). LS ≥ median was associated with higher probability of HF rehospitalizations and composite end point (all-cause death, heart transplantation, HF rehospitalisation and valve replacement therapy) both on admission (logrank p=0.004 and p=0.006) and at discharge (log-rank p=0.001 and p=0.004). Multivariable Cox regression analysis revealed that on a continuous scale LS increase per 1 kPa on admission was related to higher risk of HF hospitalization (hazard ratio [HR] 1.024, 95% confidential interval [CI] 1.002-1.046, p=0.03). LS at discharge was independently associated with increased all-cause mortality (HR per 1 kPa increase 1.098, 95% CI 1.025-1.176, p=0.008), higher risk of HF hospitalization (HR 1.075, 95% CI 1.035-1.117, p.

Dominant mutations in KBTBD13, a member of the BTB/Kelch family, cause nemaline myopathy with cores

We identified a member of the BTB/Kelch protein family that is mutated in nemaline myopathy type 6 (NEM6), an autosomal-dominant neuromuscular disorder characterized by the presence of nemaline rods and core lesions in the skeletal myofibers. Analysis of affected families allowed narrowing of the candidate region on chromosome 15q22.31, and mutation screening led to the identification of a previously uncharacterized gene, KBTBD13, coding for a hypothetical protein and containing missense mutations that perfectly cosegregate with nemaline myopathy in the studied families. KBTBD13 contains a BTB/POZ domain and five Kelch repeats and is expressed primarily in skeletal and cardiac muscle. The identified disease-associated mutations, C.742C>A (p.Arg248Ser), c.1170G>C (p.Lys390Asn), and c.1222C>T (p.Arg408Cys), located in conserved domains of Kelch repeats, are predicted to disrupt the molecule's beta-propeller blades. Previously identified BTB/POZ/Kelch-domain-containing proteins have been implicated in a broad variety of biological processes, including cytoskeleton modulation, regulation of gene transcription, ubiquitination, and myofibril assembly. The functional role of KBTBD13 in skeletal muscle and the pathogenesis of NEM6 are subjects for further studies.

The ryanodine receptor type 1 gene variants in African American men with exertional rhabdomyolysis and malignant hyperthermia susceptibility

It has been suggested that exertional rhabdomyolysis (ER) and malignant hyperthermia (MH) are related syndromes. We hypothesize that patients with unexplained ER harbor mutations in the ryanodine receptor gene type 1 (RYR1), a primary gene implicated in MH, and therefore ER patients are at increased risk for MH. Although there are reported cases of MH in individuals of African descent, there are no data available on molecular characterization of these patients. We analyzed RYR1 in six, unrelated African American men with unexplained ER, who were subsequently diagnosed as MH susceptible (MHS) by the Caffeine Halothane Contracture Test. Three novel and two variants, previously reported in Caucasian MHS subjects, were found in five studied patients. The novel variants were highly conserved amino acids and were absent among 230 control subjects of various ethnic backgrounds. These results emphasize the importance of performing muscle contracture testing and RYR1 mutation screening in patients with unexplained ER. The MHS-associated variant Ala1352Gly was identified as a polymorphism predominant in individuals of African descent. Our data underscore the need for investigating RYR1 across different ethnic groups and will contribute to interpretation of genetic screening results of individuals at risk for MH.

In-frame deletion in the seventh immunoglobulin-like repeat of filamin C in a family with myofibrillar myopathy

Myofibrillar myopathies (MFMs) are an expanding and increasingly recognized group of neuromuscular disorders caused by mutations in DES, CRYAB, MYOT, and ZASP. The latest gene to be associated with MFM was FLNC; a p.W2710X mutation in the 24th immunoglobulin-like repeat of filamin C was shown to be the cause of a distinct type of MFM in several German families. We studied an International cohort of 46 patients from 39 families with clinically and myopathologically confirmed MFM, in which DES, CRYAB, MYOT, and ZASP mutations have been excluded. In patients from an unrelated family a 12-nucleotide deletion (c.2997_3008del) in FLNC resulting in a predicted in-frame four-residue deletion (p.Val930_Thr933del) in the seventh repeat of filamin C was identified. Both affected family members, mother and daughter, but not unrelated control individuals, carried the p.Val930_Thr933del mutation. The mutation is transcribed and, based on myopathological features and immunoblot analysis, it leads to an accumulation of dysfunctional filamin C in the myocytes. The study results suggest that the novel p.Val930_Thr933del mutation in filamin C is the cause of MFM but also indicate that filamin C mutations are a comparatively rare cause of MFM.

Regulation of N-cadherin-based cell–cell interaction by JSAP1 scaffold in PC12h cells

We previously reported that the level of c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1), a scaffold protein for JNK signaling, increases dramatically during nerve growth factor (NGF)-induced differentiation of PC12h cells. In the present study, we investigated the function of JSAP1 during PC12h cell differentiation by knocking down the level of JSAP1. The depletion of JSAP1 caused NGF-treated PC12h cells to form aggregates and impaired their differentiation. The aggregation was not observed in JSAP1-depleted cells that were untreated or treated with epidermal growth factor. Immunocytochemical studies indicated that N-cadherin, but not E-cadherin, was localized to sites of cell-cell contact in the aggregated cells. Furthermore, an inhibitory anti-N-cadherin antibody completely blocked the aggregation. Taken together, these results suggest that JSAP1 regulates cell-cell interactions in PC12h cells specifically in the NGF-induced signaling pathway, and does so by modulating N-cadherin.

Selective expression of the scaffold protein JSAP1 in spermatogonia and spermatocytes

Scaffold proteins of mitogen-activated protein kinase (MAPK) intracellular signal transduction pathways mediate the efficient and specific activation of the relevant MAPK signaling modules. Previously, our group and others have identified c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1, also known as JNK-interacting protein 3) as a scaffold protein for JNK MAPK pathways. Although JSAP1 is expressed in the testis in adults, its expression during development has not been investigated. In addition, it is unknown which types of cells in the testis express the scaffold protein. Here, we examined the expression of JSAP1 in the testis of mice aged 14 days, 20 days, 6 weeks, and 12 weeks by immunohistochemistry and Western blotting. The specificity of the anti-JSAP1 antibody was evaluated from its reactivity to exogenously expressed JSAP1 and a structurally related protein, and by antigen-absorption experiments. The immunohistochemical analyses with the specific antibody showed that the JSAP1 protein was selectively expressed in the spermatogonia and spermatocytes, but not in other cell types, including spermatids and somatic cells, during development. However, not all spermatogonia and spermatocytes were immunopositive either, especially in the 12-week-old mouse testis. Furthermore, we found by Western blotting that the expression levels of JSAP1 protein vary during development; there is high expression until 6 weeks after birth, which approximately corresponds to the end of the first wave of spermatogenesis. Collectively, these results suggest that JSAP1 function may be important in spermatogenic cells during early postnatal development.