van der Vekens N, Decloedt A, de Clercq D, Ven S, Sys S, van Loon G
Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Belgium.
Equine Vet J. 2016 Jan;48(1):15-20. doi: 10.1111/evj.12362. Epub 2014 Nov 24.
Studies on the use of atrial natriuretic peptide (ANP) as a biomarker for left atrial dilatation in horses have produced variable results. Few have been performed, and the results may have been influenced by ANP instability, differences in sampling protocol and changes in the assay over time. N-Terminal proANP (NT-proANP) is a more stable molecule and might be a good alternative for clinical use.
To compare ANP and NT-proANP in terms of the detection of left atrial dilatation and to determine the influence of sample storage at temperatures of -80 and -20°C.
Prospective clinical study.
Atrial natriuretic peptide and NT-proANP concentrations were compared between healthy horses (Group 1, n = 20), horses with mitral valve regurgitation and a normal atrial size (Group 2, n = 11) and horses with mitral valve regurgitation associated with left atrial dilatation (Group 3, n = 16). The ANP concentration was measured with an equine enzyme-linked immunosorbent assay and the NT-proANP concentration with an enzyme-linked immunosorbent assay developed for use in human patients. Samples were stored at -20 and -80°C and analysed within 7 months.
The NT-proANP concentrations were not significantly different between the groups. Horses in Group 3 had a significantly higher ANP concentration (median 366 pg/ml; interquartile range [IQR] 74-2000 pg/ml) compared with horses in Group 1 (median 31 pg/ml; IQR 31-333 pg/ml) or Group 2 (median 31 pg/ml; IQR 31-1152 pg/ml; P = 0.02). The ANP cut-off value for detection of left atrial dilatation was 52 pg/ml (sensitivity 81%; specificity 84%) for sample storage at -80°C, and 44 pg/ml (sensitivity 69%; specificity 84%) for storage at -20°C. A larger decrease in ANP (45 ± 126 pg/ml) than in NT-proANP (10 ± 31 pg/ml) was found associated with sample storage at -20 instead of -80°C.
Atrial natriuretic peptide, but not NT-proANP, can be used to detect left atrial dilatation in horses. Atrial natriuretic peptide is less stable than NT-proANP when samples are stored at -20°C. Atrial natriuretic peptide is a more suitable biomarker of left atrial dilatation in horses than NT-proANP.
关于使用心房利钠肽（ANP）作为马匹左心房扩张生物标志物的研究结果不一。此类研究较少，其结果可能受到ANP不稳定性、采样方案差异以及检测方法随时间变化的影响。N末端前ANP（NT-proANP）是一种更稳定的分子，可能是临床应用的良好替代物。
比较ANP和NT-proANP在检测左心房扩张方面的差异，并确定在-80℃和-20℃温度下样本储存的影响。
前瞻性临床研究。
比较健康马匹（第1组，n = 20）、二尖瓣反流且心房大小正常的马匹（第2组，n = 11）以及二尖瓣反流伴左心房扩张的马匹（第3组，n = 16）的心房利钠肽和NT-proANP浓度。使用马酶联免疫吸附测定法测量ANP浓度，使用为人类患者开发的酶联免疫吸附测定法测量NT-proANP浓度。样本储存在-20℃和-80℃，并在7个月内进行分析。
各组间NT-proANP浓度无显著差异。与第1组（中位数31 pg/ml；四分位间距[IQR] 31 - 333 pg/ml）或第2组（中位数31 pg/ml；IQR 31 - 1152 pg/ml；P = 0.02）相比，第3组马匹的ANP浓度显著更高（中位数366 pg/ml；IQR 74 - 2000 pg/ml）。对于储存在-80℃的样本，检测左心房扩张的ANP临界值为52 pg/ml（敏感性81%；特异性84%），对于储存在-20℃的样本，临界值为44 pg/ml（敏感性69%；特异性84%）。发现与储存在-80℃相比，储存在-20℃时ANP的下降幅度（45 ± 126 pg/ml）大于NT-proANP（10 ± 31 pg/ml）。
心房利钠肽可用于检测马匹的左心房扩张，而NT-proANP不能。当样本储存在-20℃时，心房利钠肽比NT-proANP更不稳定。与NT-proANP相比，心房利钠肽是马匹左心房扩张更合适的生物标志物。
