Early diagnostic and prognostic value of myocardial strain derived from cardiovascular magnetic resonance in patients with cardiac amyloidosis.

Background: Cardiac amyloidosis (CA) is one of the causes of heart failure with preserved ejection fraction. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume (ECV) fractions is a preferred method to identify CA. However, the requirement of contrast limits its use in renal deficiency patients. Myocardial strain is a promising method without contrast. We sought to assess the early diagnostic and prognostic value of strain. Methods: This retrospective study enrolled 31 patients with systemic amyloidosis (SA) in Peking University First Hospital from January 2014 to January 2019. The patients were categorized into three groups, including 11 CA patients with left ventricular hypertrophy (CA-LVH group), 9 CA patients without LVH (CA-NLVH group), and 11 patients with extracardiac SA (SA group). Strain analysis was performed with CMR images. A least absolute shrinkage and selection operator (LASSO) was used to generate strain score. The receiver operating characteristic (ROC) curve was used to evaluate the early diagnostic efficacy of strain score and other single strain parameter. The primary endpoint was defined as death from all cause or rehospitalization for heart failure. A Cox proportional hazards model was used to assess the index value on the prognosis. Results: In CA patients, as the left ventricular wall thickens, the global and regional strain decrease significantly. A new strain score (strain score = 0.00893 × mid-septal circumferential peak strain + 0.02285 × apical radial peak strain + 0.1541 × apical circumferential peak strain + 0.33097 × epicardial circumferential average peak strain + 0.42232 × endocardial longitudinal average peak strain) generated using LASSO showed that the area under the ROC curve was 0.909. All the patients with outcome events were in CA groups, four were in CA-LVH group and one in CA-NLVH group. New York Heart Association (NYHA) grade [hazard ratio (HR) =14.29, 95% confidence interval (CI): 2.34-87.34, P<0.01], brain natriuretic peptide (HR =20.05, 95% CI: 2.21-182.36, P=0.008), cardiac injury biomarker (HR =11.59, 95% CI: 1.03-130.36, P=0.047), E/E' (mitral inflow to mitral relaxation velocity ratio) (HR =1.09, 95% CI: 1.00-1.18, P=0.040), end-systolic left ventricular volume (HR =1.04, 95% CI: 1.00-1.18, P=0.039) and LGE volume (HR =1.11, 95% CI: 1.02-1.20, P=0.012) positively correlate with events. Better renal function (HR =0.92, 95% CI: 0.86-0.98, P=0.011) and ejection fraction (HR =0.94, 95% CI: 0.88-0.99, P=0.027) appear to be protective factors. Although with no statistical difference, the strain damage had a tendency to predict poor prognosis, i.e., mid-ventricular circumferential strain with HR of 1.25 (95% CI: 1.0-1.57, P=0.050) and strain score with HR of 1.30 (95% CI: 0.98-1.73, P=0.067). Conclusions: Myocardial strain decreased in CA patients. The integrated magnetic resonance imaging (MRI) strain score can serve as a useful tool to identify early myocardial involvement in amyloidosis. The strain damage had a tendency to predict poor prognosis.

Improved diagnosis of type-1 diabetes mellitus using multiplexed autoantibodies ELISA array.

Autoantibodies are currently the most robust biomarkers of type 1 diabetes. However, single autoantibody targeted detection is still limited in diabetes diagnosis with poor performance. Here, we develop a multiplexed Array-ELISA assay that can detect five diabetes-related autoantibodies including glutamic acid decarboxylase antibody (GADA), insulinoma antigen 2 antibody (IA-2A), islet cell antibody (ICA), zinc transporter 8 autoantibody (ZnT8-A) and insulin antibody (IAA) simultaneously. This assay achieved 100% accuracy in identifying the positive and negative control samples with good repeatability (CV<15%). We applied the Array-ELISA assay to 140 clinical serum samples of healthy subjects and diabetes patients and the assay showed improved diagnosis accuracy (sensitivity of 62.5%, specificity of 94.3%) compared with the single target immunoblotting test. These data suggest that the Array-ELISA assay can provide diagnostic and predictive ability in the clinical practice of type 1 diabetes.

Molecular cloning and expression analysis of cytochrome P450 3A gene in the turbot Scophthalmus maximus.

In this study, the cytochrome P450 3A (CYP3A) gene was cloned from the turbot Scophthalmus maximus for the first time using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends approaches. The amino acid sequences were analyzed with corresponding software programs. The cDNA of CYP3A was 1,969 bp in length, which contained a 5'-untranslated region (UTR) of 34 bp, a 3'-UTR of 404 bp and an open reading frame of 1,530 bp encoding a predicted protein of 509 amino acids (GenBank accession No. JN216889). The deduced protein had a molecular weight of 58.09 kDa and an isoelectric point of 5.75. Amino acid sequence alignment indicated that turbot CYP3A shared 60-67% homology with other fish species. It consists of a signal peptide, six conservative substrate recognition sites (SRS 1-6) and the conserved heme-binding motif FXXGXXXCXG in all CYP3As. Quantitative real-time RT-PCR analysis indicated that turbot CYP3A mRNA was widely expressed in liver, kidney, gill, muscle, stomach, intestine, gallbladder and spleen, with the highest level in liver and the lowest in muscle. After oral administration of sulfamethazine, CYP3A expression in all experimental groups enhanced compared with control, and the expression varied with administration time. It suggested that CYP3A expression could be induced by sulfamethazine. Our findings provided molecular characterization and expression profile of turbot CYP3A, and revealed the important role that turbot CYP3A played in drug metabolisms.

Mutations in the C. elegans succinate dehydrogenase iron-sulfur subunit promote superoxide generation and premature aging.

The mitochondrial succinate dehydrogenase (SDH) is an iron-sulfur flavoenzyme linking the Krebs cycle and the mitochondrial respiratory chain. Mutations in the human SDHB, SDHC and SDHD genes are responsible for the development of paraganglioma and pheochromocytoma, tumors of the head and neck or the adrenal medulla, respectively. In recent years, SDH has become recognized as a source of reactive oxygen species, which may contribute to tumorigenesis. We have developed a Caenorhabditis elegans model to investigate the molecular and catalytic effects of mutations in the sdhb-1 gene, which encodes the SDH iron-sulfur subunit. We created mutations in Pro211; this residue is located near the site of ubiquinone reduction and is conserved in human SDHB (Pro197), where it is associated with tumorigenesis. Mutant phenotypes ranged from relatively benign to lethal and were characterized by hypersensitivity to oxidative stress, a shortened life span, impaired respiration and overproduction of superoxide. Our data suggest that the SDH ubiquinone-binding site can become a source of superoxide and that the pathological consequences of SDH mutations can be mitigated with antioxidants, such as ascorbate and N-acetyl-l-cysteine. Our work leads to a better understanding of the relationship between genotype and phenotype in respiratory chain mutations and of the mechanisms of aging and tumorigenesis.