Plasma nitric oxide in dogs with pulmonary hypertension secondary or not to left-sided heart disease

ABSTRACT Nitric oxide (NO) is an important mediator responsible for vasodilation in pulmonary hypertension (PH) in humans. Based on human literature, it is suggested that in dogs there is also NO production decrease in lung tissue in the presence of PH with hypoxia. Therefore, the aim of this research was to determine the indirect plasmatic NO concentration in dogs with PH secondary or not to the left-side heart disease (LHD) and also with low, intermediate and high probability of PH to characterize the NO involvement on PH in dogs. Blood samples were collected from 35 dogs with probability of PH to NO measurement. NO concentration was estimated by the nitrite/nitrate concentration, and it was significantly different (p=0.002) in dogs with PH secondary to LHD (median=14 µM, range 11.19-16.59) and not secondary to LHD (median=25.88µM, range 15.08-36.71). However, this was not significant for the probability of low, intermediate, and high PH, although there was a tendency for NO concentration to be higher in dogs with high PH. The results of this study demonstrate that there is release of NO in dogs with PH, as well as that its dosage could differentiate dogs with PH secondary to LHD from dogs with non-secondary PH.

摘要 一氧化氮（Nitric oxide, NO）是人类肺动脉高压（pulmonary hypertension, PH）中介导血管舒张的重要介质。基于人类医学文献，有研究提示低氧合并肺动脉高压时，犬肺组织的一氧化氮生成也会减少。因此本研究旨在检测继发或非继发于左侧心脏病（left-side heart disease, LHD）的肺动脉高压犬，以及具有低、中、高肺动脉高压概率的犬的间接血浆一氧化氮浓度，以明确一氧化氮在犬肺动脉高压发病机制中的作用。本研究共收集35例疑似肺动脉高压犬的血液样本用于一氧化氮检测，通过亚硝酸盐/硝酸盐浓度估算一氧化氮浓度。结果显示，继发于左侧心脏病的肺动脉高压犬（中位数14μM，范围11.19~16.59μM）与非继发于左侧心脏病的肺动脉高压犬（中位数25.88μM，范围15.08~36.71μM）的血浆一氧化氮浓度存在显著差异（p=0.002）。不过，不同肺动脉高压概率分层（低、中、高）的犬群间，该浓度差异未达到统计学显著性，尽管高概率肺动脉高压犬的一氧化氮浓度呈现升高趋势。本研究结果证实，肺动脉高压犬体内存在一氧化氮释放，且通过检测其血浆浓度可区分继发于左侧心脏病的肺动脉高压犬与非继发性肺动脉高压犬。