Adiponectin serum level is an independent and incremental predictor of all-cause mortality after transcatheter aortic valve replacement.

BACKGROUND: Quantifiable biomarkers may be useful for a better risk and frailty assessment of patients referred for transcatheter aortic valve implantation (TAVI). HYPOTHESIS: To determine if adiponectin serum concentration predicts all-cause mortality in patients undergoing TAVI. METHODS: 77 consecutive patients, undergoing TAVI, were analyzed. The CT axial slices at the level of the fourth lumbar vertebra were used to measure the psoas muscle area, and its low-density muscle fraction (LDM (%)). To assess the operative risk, the STS (Society of Thoracic Surgeons Predicted Risk of Mortality) score, Log. Euroscore, and Euroscore II were determined. A clinical frailty assessment was performed. ELISA kits were used to measure adiponectin serum levels. We searched for a correlation between serum adiponectin concentration and all-cause mortality after TAVI. RESULTS: The mean age was 80.8 ± 7.4 years. All-cause mortality occurred in 22 patients. The mean follow-up was 1779 days (range: 1572-1825 days). Compared with patients with the lowest adiponectin level, patients in the third tertile had a hazards ratio of all-cause mortality after TAVI of 4.155 (95% CI: 1.364-12.655) (p = .004). In the multivariable model, including STS score, vascular access of TAVI procedure, LDM (%), and adiponectin serum concentration, serum adiponectin level, and LDM(%) were independent predictors of all-cause mortality after TAVI (p = .178, .303, .042, and .017, respectively). Adiponectin level was a predictor of all-cause mortality in females and males (p = .012 and 0.024, respectively). CONCLUSION: Adiponectin serum level is an independent and incremental predictor of all-cause mortality in patients undergoing TAVI.

Rare missense mutations in ABCA7 might increase Alzheimer's disease risk by plasma membrane exclusion.

The adenosine triphosphate-binding cassette subfamily A member 7 gene (ABCA7) is associated with Alzheimer's disease (AD) in large genome-wide association studies. Targeted sequencing of ABCA7 suggests a role for rare premature termination codon (PTC) mutations in AD, with haploinsufficiency through nonsense-mediated mRNA decay as a plausible pathogenic mechanism. Since other classes of rare variants in ABCA7 are poorly understood, we investigated the contribution and pathogenicity of rare missense, indel and splice variants in ABCA7 in Belgian AD patient and control cohorts. We identified 8.36% rare variants in the patient cohort versus 6.05% in the control cohort. For 10 missense mutations identified in the Belgian cohort we analyzed the pathogenetic effect on protein localization in vitro using immunocytochemistry. Our results demonstrate that rare ABCA7 missense mutations can contribute to AD by inducing protein mislocalization, resulting in a lack of functional protein at the plasma membrane. In one pedigree, a mislocalization-inducing missense mutation in ABCA7 (p.G1820S) co-segregated with AD in an autosomal dominant inheritance pattern. Brain autopsy of six patient missense mutation carriers showed typical AD neuropathological characteristics including cerebral amyloid angiopathy type 1. Also, among the rare ABCA7 missense mutations, we observed mutations that affect amino acid residues that are conserved in ABCA1 and ABCA4, of which some correspond to established ABCA1 or ABCA4 disease-causing mutations involved in Tangier or Stargardt disease.

The role of ATP-binding cassette subfamily A in the etiology of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is the leading cause of dementia, clinically characterized by memory deficits and progressive cognitive decline. Despite decades of research effective therapies are lacking, and a large part of the genetic heritability remains unidentified. ABCA7 and ABCA1, members of the ATP-binding cassette subfamily A (ABCA), were identified as AD risk genes in genome-wide association studies. Nevertheless, genetic and/or functional studies propose a link between AD and two other members of the ABCA subclass, i.e., ABCA2 and ABCA5. MAIN BODY: Changes in expression or dysfunction of these transporters were found to increase amyloid ß levels. This might be related to the common role of ABCA transporters in cellular cholesterol homeostasis, for which a prominent role in AD development has been suggested. In this review, we provide a comprehensive overview and discussion on the contribution of the ABCA subfamily to the etiopathogenesis of AD. CONCLUSIONS: A better understanding of the function and identification of disease-associated genetic variants in ABCA transporters can contribute to the development of novel therapeutic strategies for AD.

Computed tomography measured psoas muscle attenuation predicts mortality after transcatheter aortic valve implantation.

AIMS: The aim of this study was to determine if computed tomography (CT) psoas muscular attenuation measurements may predict all-cause mortality in patients undergoing TAVI. METHODS: Ninety-four consecutive patients undergoing TAVI were analysed. The CT axial slice at the level of the fourth lumbar vertebra was selected. The psoas muscle areas were manually contoured. The circumferential surface area (CSA) of both psoas muscles was determined by selecting the voxels with attenuation values, ranging from 0 to 100 Hounsfield Units (HU). The mean CT attenuation coefficient of the psoas muscle (Psoas mean HU) was measured. The muscle was subdivided into a low-density muscle (LDM) (0-29 HU) and high-density muscle (HDM) (30-100 HU) portion. The HDM/LDM ratio was calculated. We searched for a correlation between HDM/LDM, CSA LDM (%), Psoas mean HU and all-cause mortality. RESULTS: The mean age was 81.2 ±â€Š7.5 years. Thirty patients had adverse outcome (all-cause mortality). Compared with patients with the lowest CSA LDM (%), patients in the third and second tertiles had an increased hazard ratio for mortality (2.871; 95% confidence interval 0.880-9.371 and 5.044; 95% confidence interval 1.641-15.795, respectively) in a multivariable model with EuroSCORE II, Barthel frailty index and CSA LDM (%) (P = 0.231, 0.097 and 0.019, respectively). HDM/LDM and Psoas mean HU (as continuous variable) were also independent predictors of all-cause mortality (P = 0.019, P = 0.013, respectively). CONCLUSION: CSA LDM (%), Psoas mean HU and HDM/LDM are independent and incremental predictors of all-cause mortality in patients undergoing TAVI.

Premature termination codon mutations in ABCA7 contribute to Alzheimer's disease risk in Belgian patients.

The ATP-Binding Cassette Subfamily A Member 7 gene (ABCA7) was identified as a risk gene for Alzheimer's disease (AD) in genome-wide association studies of large cohorts of late-onset AD (LOAD) patients. Extended resequencing of the ABCA7 coding regions identified mutations that lead to premature termination codons (PTC) and loss of function of ABCA7. PTC mutations were enriched in LOAD patients and were frequently present in patients with early-onset AD (EOAD). We aimed at assessing the contribution of ABCA7 PTC mutations to AD in the Belgian population by screening the ABCA7 coding region in a Belgian AD cohort of 1376 patients, including LOAD and EOAD patients, and in a Belgian control cohort of 976 individuals. We identified a PTC mutation in 67 AD patients (4.9%) and in 18 control individuals (1.8%) confirming the enrichment of ABCA7 PTC mutations in Belgian AD patients. The patient carriers had a mean onset age of 69.7 ± 9.8 years with a wide onset age range of 42 years (48-90 years). In 77.3% of the families of ABCA7 carriers, there were AD patients present suggestive of a positive family history of disease, but a Mendelian co-segregation of ABCA7 PTC mutations with disease is not clear. Overall, our genetic data predict that PTC mutations in ABCA7 are common in the Belgian population and are present in LOAD and EOAD patients.

NanoSatellite: accurate characterization of expanded tandem repeat length and sequence through whole genome long-read sequencing on PromethION.

Technological limitations have hindered the large-scale genetic investigation of tandem repeats in disease. We show that long-read sequencing with a single Oxford Nanopore Technologies PromethION flow cell per individual achieves 30× human genome coverage and enables accurate assessment of tandem repeats including the 10,000-bp Alzheimer's disease-associated ABCA7 VNTR. The Guppy "flip-flop" base caller and tandem-genotypes tandem repeat caller are efficient for large-scale tandem repeat assessment, but base calling and alignment challenges persist. We present NanoSatellite, which analyzes tandem repeats directly on electric current data and improves calling of GC-rich tandem repeats, expanded alleles, and motif interruptions.