Assessment of carotid atherosclerotic disease using three-dimensional cardiovascular magnetic resonance vessel wall imaging: comparison with digital subtraction angiography.

BACKGROUND:A three-dimensional (3D) cardiovascular magnetic resonance (CMR) vessel wall imaging (VWI) technique based on 3D T1 weighted (T1w) Sampling Perfection with Application-optimized Contrast using different flip angle Evolutions (SPACE) has recently been used as a promising CMR imaging modality for evaluating extra-cranial and intra-cranial vessel walls. However, this technique is yet to be validated against the current diagnostic imaging standard. We therefore aimed to evaluate the diagnostic performance of 3D CMR VWI in characterizing carotid disease using intra-arterial digital subtraction angiography (DSA) as a reference. METHODS:Consecutive patients with at least unilateral > 50% carotid stenosis on ultrasound were scheduled to undergo interventional therapy were invited to participate. The following metrics were measured using 3D CMR VWI and DSA: lumen diameter of the common carotid artery (CCA) and segments C1-C7, stenosis diameter, reference diameter, lesion length, stenosis degree, and ulceration. We assessed the diagnostic sensitivity, specificity, accuracy, and receiver operating characteristic (ROC) curve of 3D CMR VWI, and used Cohen's kappa, the intraclass correlation coefficient (ICC), and Bland-Altman analyses to assess the diagnostic agreement between 3D CMR VWI and DSA. RESULTS:The ICC (all ICCs ≥0.96) and Bland-Altman plots indicated excellent inter-reader agreement in all individual morphologic measurements by 3D CMR VWI. Excellent agreement in all individual morphologic measurements were also found between 3D CMR VWI and DSA. In addition, 3D CMR VWI had high sensitivity (98.4, 97.4, 80.0, 100.0%), specificity (100.0, 94.5, 99.1, 98.0%), and Cohen's kappa (0.99, 0.89, 0.84, 0.96) for detecting stenosis > 50%, stenosis > 70%, ulceration, and total occlusion, respectively, using DSA as the standard. The AUC of 3D CMR VWI for predicting stenosis > 50 and > 70% were 0.998 and 0.999, respectively. CONCLUSIONS:The 3D CMR VWI technique enables accurate diagnosis and luminal feature assessment of carotid artery atherosclerosis, suggesting that this imaging modality may be useful for routine imaging workups and provide comprehensive information for both the vessel wall and lumen

Effects of Exogenous Abscisic Acid on Bioactive Components and Antioxidant Capacity of Postharvest Tomato during Ripening

Abscisic acid (ABA) is a phytohormone which is involved in the regulation of tomato ripening. In this research, the effects of exogenous ABA on the bioactive components and antioxidant capacity of the tomato during postharvest ripening were evaluated. Mature green cherry tomatoes were infiltrated with either ABA (1.0 mM) or deionized water (control) and stored in the dark for 15 days at 20 °C with 90% relative humidity. Fruit colour, firmness, total phenolic and flavonoid contents, phenolic compounds, lycopene, ascorbic acid, enzymatic activities, and antioxidant capacity, as well as the expression of major genes related to phenolic compounds, were periodically monitored. The results revealed that exogenous ABA accelerated the accumulations of total phenolic and flavonoid contents; mostly increased the contents of detected phenolic compounds; enhanced FRAP and DPPH activity; and promoted the activities of PAL, POD, PPO, CAT, and APX during tomato ripening. Meanwhile, the expressions of the major genes (PAL1, C4H, 4CL2, CHS2, F3H, and FLS) involved in the phenylpropanoid pathway were up-regulated (1.13- to 26.95-fold) in the tomato during the first seven days after treatment. These findings indicated that ABA promoted the accumulation of bioactive components and the antioxidant capacity via the regulation of gene expression during tomato ripening

Comparative Transcriptome Analysis Reveals the Influence of Abscisic Acid on the Metabolism of Pigments, Ascorbic Acid and Folic Acid during Strawberry Fruit Ripening

<div><p>A comprehensive investigation of abscisic acid (ABA) biosynthesis and its influence on other important phytochemicals is critical for understanding the versatile roles that ABA plays during strawberry fruit ripening. Using RNA-seq technology, we sampled strawberry fruit in response to ABA or nordihydroguaiaretic acid (NDGA; an ABA biosynthesis blocker) treatment during ripening and assessed the expression changes of genes involved in the metabolism of pigments, ascorbic acid (AsA) and folic acid in the receptacles. The transcriptome analysis identified a lot of genes differentially expressed in response to ABA or NDGA treatment. In particular, genes in the anthocyanin biosynthesis pathway were actively regulated by ABA, with the exception of the gene encoding cinnamate 4-hydroxylase. Chlorophyll degradation was accelerated by ABA mainly owing to the higher expression of gene encoding pheide a oxygenase. The decrease of β-carotene content was accelerated by ABA treatment and delayed by NDGA. A high negative correlation rate was found between ABA and β-carotene content, indicating the importance of the requirement for ABA synthesis during fruit ripening. In addition, evaluation on the folate biosynthetic pathway indicate that ABA might have minor function in this nutrient’s biosynthesis process, however, it might be involved in its homeostasis. Surprisingly, though AsA content accumulated during fruit ripening, expressions of genes involved in its biosynthesis in the receptacles were significantly lower in ABA-treated fruits. This transcriptome analysis expands our understanding of ABA’s role in phytochemical metabolism during strawberry fruit ripening and the regulatory mechanisms of ABA on these pathways were discussed. Our study provides a wealth of genetic information in the metabolism pathways and may be helpful for molecular manipulation in the future.</p></div

Genes identified in the metabolism network of pigments, folic acid and ascorbic acid during strawberry fruit ripening.

<p>Pathways, including anthocyanin, carotenoid, ascorbic acid and folic acid biosynthesis and chlorophyll degradation, are shown. Genes encoding enzymes with blue names were significantly differentially expressed among samples, and those encoding enzymes with purple names were identified as non-significantly differentially expressed. The chloroplast is separated from the plastid to clearly illustrate the chlorophyll breakdown pathway. Abbreviations: (anthocyanin biosynthetic pathway) 3-deoxy-7-phosphoheptulonate synthase, DAHPS; 3-dehydroquinate synthase, DHQS; 3-dehydroquinate dehydratase/shikimate dehydrogenase, DHD/SHD; Shikimate kinase, SK; 5-enolpyruvylshikimate-3-phosphate synthase, EPSPS; chorismate synthase, CS; chorismate mutase, CM; phenylalanine ammonia lyase, PAL; cinnamate 4-hydroxylase, C4H; <i>p</i>-coumarate ligase, 4CL; chalcone synthase, CHS; chalcone isomerase, CHI; flavanone 3-hydroxylase, F3H; dihydroflavonol 4-reductase, DFR; anthocyanidin synthase, ANS; glucosyltransferase, GT; (carotenoid biosynthetic pathway) 1-deoxy-D-xylulose-5-phosphate synthase, DXS; 1-deoxy-D-xylulose-5-phosphate reductoisomerase, DXR; 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, CMS; 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase, CMK; 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase, MCS; isopentenyl-diphosphate delta-isomerase, IPI; geranyl diphosphate synthase, GGPS; geranylgeranyl reductase, GGR; phytoene synthase, PSY; phytoene desaturase, PDS; zeta-carotene isomerase, Z-ISO; zeta-carotene desaturase, ZDS; carotenoid isomerase, CRTISO; lycopene beta cyclase, LCYB; zeaxanthin epoxidase, ZEP; violaxanthin de-epoxidase, VDE; acetyl-CoA C-acetyltransferase, ACAT; hydroxymethylglutaryl-CoA synthase, HMGCS; mevalonate kinase, MVK; phosphomevalonate kinase, PMVK; farnesyl diphosphate synthase, FPPS. (Chlorophyll breakdown pathway) pheophorbide a oxygenase, PAO; red chlorophyll catabolite reductase, RCCR. (ascorbic acid biosynthetic pathway) glucose-6-phosphate isomerase, GPI; mannose-6-phosphate isomerase, MPI; phosphomannomutase, PMM; mannose-1-phosphate guanyltransferase, GMPPB; GDP-mannose 3,5-epimerase, GME; GDP-L-galactose phosphorylase, GGP; L-galactose dehydrogenase, GDH; L-galactono-1,4-lactone dehydrogenase, GLDH. (folate biosynthetic pathway) para-aminobenzoate synthase, pABS; dihydropteroate synthase, DHPS; gamma-glutamyl hydrolase, GGH. For the abbreviations of other metabolites, please refer to the manuscript.</p

Differentially expressed genes involved in the ascorbic acid biosynthesis pathway.

<p>CK, ABA, and NDGA represent fruit treated with water, ABA, or NDGA, respectively. Only the receptacle samples were collected for RNA-seq analysis. Red and green colors mean up- and down-regulated expression of genes, respectively. The number in each sample name represents the collection day.</p

Transcriptomic Analysis Reveals Possible Influences of ABA on Secondary Metabolism of Pigments, Flavonoids and Antioxidants in Tomato Fruit during Ripening

<div><p>Abscisic acid (ABA) has been proven to be involved in the regulation of climacteric fruit ripening, but a comprehensive investigation of its influence on ripening related processes is still lacking. By applying the next generation sequencing technology, we conducted a comparative analysis of the effects of exogenous ABA and NDGA (Nordihydroguaiaretic acid, an inhibitor of ABA biosynthesis) on tomato fruit ripening. The high throughput sequencing results showed that out of the 25728 genes expressed across all three samples, 10388 were identified as significantly differently expressed genes. Exogenous ABA was found to enhance the transcription of genes involved in pigments metabolism, including carotenoids biosynthesis and chlorophyll degradation, whereas NDGA treatment inhibited these processes. The results also revealed the crucial role of ABA in flavonoids synthesis and regulation of antioxidant system. Intriguingly, we also found that an inhibition of endogenous ABA significantly enhanced the transcriptional abundance of genes involved in photosynthesis. Our results highlighted the significance of ABA in regulating tomato ripening, which provided insight into the regulatory mechanism of fruit maturation and senescence process.</p></div

Differentially expressed genes involved in the anthocyanin biosynthesis pathway in response to ABA or NDGA treatment.

<p>CK, ABA, and NDGA represent fruit treated with water, ABA, or NDGA, respectively. Only the receptacle samples were collected for RNA-seq analysis. Red and green colors mean up- and down-regulated expression of genes, respectively. The number in each sample name represents the collection day.</p