Heart Block as a Rare Complication of Tricuspid Valve Endocarditis: Awareness is the Key.

Infective endocarditis (IE) occurs when bacterial or fungal pathogens enter the blood and attach to the endocardium. Right-sided endocarditis is usually associated with intravenous drug use (IVDU), intracardiac devices, and central venous catheters. There is more data published about left-side endocarditis when compared to right-sided endocarditis. Tricuspid valve infective endocarditis (TVIE) accounts for 5%-10% of IE, and of those cases, roughly 10% are complicated by conduction deficits due to inflammatory edema, myocarditis, and abscess formation. Tricuspid valve (TV) surgical repair carries its own risks, one of which includes the development of conduction abnormalities. Here, we review the current data of TVIE complicated by heart block after tricuspid valve replacement. Also, we present a case of a 21-year-old IVDU female who presented with tricuspid valve endocarditis, subsequently underwent tricuspid valve replacement, and developed a heart block.

The mechanism of Megalobrama amblycephala muscle injury repair based on RNA-seq.

Skeletal muscle myogenesis and injury-induced muscle regeneration contribute to muscle formation. Skeletal muscle stem cells, termed satellite cells (SCs), proliferate to repair injured muscle. To identify the molecular mechanism of regeneration after muscle injury as well as the genes related to muscle development in fish, in this study, the immunohistochemistry and the high-throughput RNA sequencing (RNA-seq) analysis were performed after Megalobrama amblycephala muscle was injured by needle stab. The results showed that paired box7-positive (Pax7+) SCs increased, and peaked at 96 to 144 h-post injury (hpi). The 6729 differentially expressed genes (DEGs), including 2125 up-regulated and 4604 down-regulated genes were found. GO terms significantly enriched by DEGs contained intercellular connections, signaling transduction and enzyme activity. KEGG enrichment analysis showed that most of the pathways were related to immunity, metabolism and cells related molecules, including actin skeleton regulation, Epstein Barr virus infection and plaque adhesion. The WGCNA results revealed that actin cytoskeleton and lipid metabolism related genes probably played crucial roles during repair after muscle injury. Collectively, all these results will provide new insights into the molecular mechanisms underlying muscle injury repair of fish.

Transcriptomic analysis of gills in nitrite-tolerant and -sensitive families of Litopenaeus vannamei.

Nitrite stress is a major environmental factor that limits aquatic animal growth, reproduction and survival. Even so, some shrimps still can withstand somewhat high concentrations of nitrite environment. However, few studies have been conducted about the tolerance molecular mechanism of Litopenaeus vannamei in the high concentration nitrite. To identify the genes and pathways involved in the regulation of nitrite tolerance, we performed comparative transcriptomic analysis in the L. vannamei nitrite-tolerant (NT) and nitrite-sensitive (NS) families, and untreated shrimps were used as the control group. After 24 h of nitrite exposure (NaNO2, 112.5 mg/L), a total of 1521 and 868 differentially expressed genes (DEGs) were obtained from NT compared with NS and control group, respectively. Functional enrichment analysis revealed that most of these DEGs were involved in immune defense, energy metabolism processes and endoplasmic reticulum (ER) stress. During nitrite stress, energy metabolism in NT was significantly enhanced by activating the related genes expression of oxidative phosphorylation (OXPHOS) pathway and tricarboxylic acid (TCA) cycle. Meanwhile, some DEGs involved in innate immunity- related genes and pathways, and ER stress responses also were highly expressed in NT. Therefore, we speculate that accelerated energy metabolism, higher expression of immunity and ER related genes might be the important adaptive strategies for NT in relative to NS under nitrite stress. These results will provide new insights on the potential tolerant molecular mechanisms and the breeding of new varieties of nitrite tolerant L. vannamei.

Integrated analysis of physiological, transcriptomic and metabolomic responses and tolerance mechanism of nitrite exposure in Litopenaeus vannamei.

Nitrite accumulation in aquatic environments is a potential risk factor that disrupts multiple physiological functions in aquatic animals. In this study, the physiology, transcriptome and metabolome of the control group (LV-C), nitrite-tolerance group (LV-NT) and nitrite-sensitive group (LV-NS) were investigated to identify the stress responses and mechanisms underlying the nitrite tolerance of Litopenaeus vannamei. After LV-NT and LV-NS were subjected to nitrite stress, the hemocyanin contents were significantly decreased, and hepatopancreas showed severe histological damage compared with LV-C. Likewise, the antioxidant enzymes were also significantly changed after nitrite exposure. The transcriptome data revealed differentially expressed genes associated with immune system, cytoskeleton remodeling and apoptosis in LV-NT and LV-NS. The combination of transcriptomic and metabolomic analysis revealed nitrite exposure disturbed metabolism processes in L. vannamei, including amino acid metabolism, nucleotide metabolism and lipid metabolism. The multiple comparative analysis implicated that higher nitrite tolerance of LV-NT than LV-NS may be attributed to enhanced hypoxia inducible factor-1α expression to regulate energy supply and gaseous exchange. Moreover, LV-NT showed higher antioxidative ability, detoxification gene expression and enhanced fatty acids contents after nitrite exposure in relative to LV-NS. Collectively, all these results will greatly provide new insights into the molecular mechanisms underlying the stress responses and tolerance of nitrite exposure in L. vannamei.