Characteristics of non-valvular atrial fibrillation patients who benefit most from anticoagulation treatment.

OBJECTIVES: The objective was to determine who will benefit most from oral anticoagulation (OAC) for non-valvular atrial fibrillation (NVAF) patients aged ≥ 75 years. BACKGROUND: It was unclear whether all of NVAF aged ≥ 75 should receive OAC. METHODS: We recruited NVAF ≥ 75 years without QAC who were divided into three groups according to CHA2DS-VASc scores. The clinical endpoints were ischemic stroke (IS), thromboembolism (TE), or death. RESULTS: The patients with CHA2DS2-VASc score of 6-9 were not appropriate for anticoagulation with the highest HAS-BLED scores. CHA2DS2-VASc of 2 had little risk for IS/TE. We further divided CHA2DS2-VASc of 3-5 into three subgroups with estimated glomerular filtration rate (eGFR; ml/min/1.73 m(2)): < 30, 30-60, and > 60. The patients with eGFR < 30 had the highest bleeding risk with a comparable IS/TE. CONCLUSIONS: NVAF with CHA2DS2-VASc of 3-5 and eGFR > 30 ml/min/1.73 m(2) represent the most appropriate population for anticoagulation.

A novel RNAi library based on partially randomized consensus sequences of nuclear receptors: identifying the receptors involved in amyloid beta degradation.

Combinatorial gene inactivation using an RNAi library is a powerful approach to discovering novel functional genes. However, generation of a comprehensive RNAi library remains technically challenging. In this report, we describe a simple and novel approach to designing gene-family-specific RNAi libraries by targeting conserved motifs using degenerate oligonucleotides. We created an siRNA library in the pHUMU vector using partially randomized sequences targeting the consensus region in the ZnF_C4 signature motif of the nuclear hormone receptors and thus against the entire receptor superfamily. For proof of principle, we adapted a reporter assay to screen this library for receptors that might be involved in reducing amyloid beta peptide accumulation. We modified a previously described luciferase reporter assay to measure the amyloid beta precursor cleavages occurring only between beta- and gamma-secretase cleavage sites, thus excluding the major gamma-secretase activities that could generate neurotoxic Abeta peptides. Our screen using this assay identified siRNA vectors that specifically increase the Abeta40/42 cleavage and pointed to a potential receptor target, ROR-gamma. SiRNAs targeting other regions of ROR-gamma not only confirmed the observed reporter activity but also reduced the level of the toxic Abeta peptides. The results demonstrated a general principle for the creation and application of this RNAi library approach for functional gene discovery within a predefined protein family. The discovered negative effect of ROR-gamma on the degradation of the toxic Abeta peptides may also provide a potential drug target or targetable pathway for intervention of Alzheimer disease.

Regulation of gene expression in response to brain injury: enhanced expression and alternative splicing of rat prosaposin (SGP-1) mRNA in injured brain.

Prosaposin, the precursor of saposins or saps, is an injury-repair protein that acts on both neurons and glia. Previous studies identified the prosaposin gene as one of differentially expressed genes following nerve injury. In the present study, we investigated expression of prosaposin mRNA in injured brain utilizing rat models of focal cerebral ischemia and cortical stab wound in order to explore the significance of prosaposin in nerve injury. In ischemic brain, the level of prosaposin mRNA was elevated greater than 400% over controls within 5 days after ischemic insults. Importantly, this induction was accompanied by a 9-base splicing consistent with the alternative Exon-8 splicing of human prosaposin mRNA. In normal brain, two prosaposin mRNA species with and without the 9-base insertion were expressed at a ratio of 85:15; however, this equilibrium reverted to 5:95 following ischemic injury. Similar inductions were observed in stab wound brains. Immunohistochemical staining and in situ hybridization demonstrated an enhanced signal distribution of prosaposin mRNA and injury-induced prosaposin protein around the lesion. The data suggest the expression and processing of prosaposin mRNA may be crucially regulated not only for cerebral homeostasis but also during nerve regenerative and degenerative processes.