Identification of key genes in calcific aortic valve disease via weighted gene co-expression network analysis.

BACKGROUND: Calcific aortic valve disease (CAVD) is the most common subclass of valve heart disease in the elderly population and a primary cause of aortic valve stenosis. However, the underlying mechanisms remain unclear. METHODS: The gene expression profiles of GSE83453, GSE51472, and GSE12644 were analyzed by 'limma' and 'weighted gene co-expression network analysis (WGCNA)' package in R to identify differentially expressed genes (DEGs) and key modules associated with CAVD, respectively. Then, enrichment analysis was performed based on Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, DisGeNET, and TRRUST database. Protein-protein interaction network was constructed using the overlapped genes of DEGs and key modules, and we identified the top 5 hub genes by mixed character calculation. RESULTS: We identified the blue and yellow modules as the key modules. Enrichment analysis showed that leukocyte migration, extracellular matrix, and extracellular matrix structural constituent were significantly enriched. SPP1, TNC, SCG2, FAM20A, and CD52 were identified as hub genes, and their expression levels in calcified or normal aortic valve samples were illustrated, respectively. CONCLUSIONS: This study suggested that SPP1, TNC, SCG2, FAM20A, and CD52 might be hub genes associated with CAVD. Further studies are required to elucidate the underlying mechanisms and provide potential therapeutic targets.

Molecular epidemiology and antimicrobial susceptibility of Clostridium difficile isolated from the Chinese People's Liberation Army General Hospital in China.

Clostridium difficile is a Gram-positive, spore-forming obligate anaerobe responsible for antibiotic-associated diarrhoea. Its virulence is associated with the production of endotoxins A and B and endospores, which can cause symptoms, such as diarrhoea, toxic megacolon, and pseudomembranous colitis. Given the increasing elderly population and the well-recognized problem of over-prescribing of broad-spectrum antibiotics, it is critical to have an understanding of molecular epidemiology and antimicrobial susceptibility in China. This study analyzed the toxin types and multilocus sequence typing (MLST) results of 74 clinical isolates of C. difficile after the glutamate dehydrogenase (GDH) screening test and anaerobic culture. The minimum inhibitory concentrations (MICs) of four different antibiotics were determined for all of the isolates, and the bacterial resistance mechanisms were investigated. Sixty-five strains (75%) were toxigenic, including 54 tcdA-positive, tcdB-positive, and cdtA/cdtB-negative strains (A+B+CDT-) and nine A-B+CDT- strains. Eleven strains (14.9%) were non-toxigenic. All clinical isolates were classified into 26 MLST genotypes, with the predominant type being ST-54 (18.9%). All isolates were susceptible to vancomycin. The tetracycline, clindamycin, and levofloxacin resistance rates were 1.4%, 36.5%, and 20.3%, respectively. The expression of tet(M), erm(B), and mutations of gyrA and/or gyrB were observed in the tetracycline-, clindamycin-, and levofloxacin-resistant isolates, respectively.