Mohamed Sagad O O, Mohammed Amged, Mohamed Tarteel, Fadil Hanaa, Salih Mohamed S K, Mohamed Amna H, Alhassan Alrumaisa, Saeed Safaa G A, Salih Fatima S K, Mustafa Huda M A, Ahmed Somaia M M, Garalnabi Esraa M A, Yousif Nadeen M, Ahmed Alaa N N, Mohamedali Abdalla O O
University of Khartoum, Khartoum, Sudan.
Médecins Sans Frontières, Geneva, Switzerland.
BMC Pulm Med. 2025 Apr 14;25(1):182. doi: 10.1186/s12890-025-03654-5.
Surfactant decreases surface tension in the peripheral airways and plays a role in regulating the lung's immune responses. Several reports have documented changes in surfactant proteins levels, especially surfactant protein D (SP-D) and surfactant protein A (SP-A), suggesting their potential as biomarkers for asthma. However, the results of these studies are controversial. This systematic review was done to assess the levels of surfactant proteins in asthmatic patients compared to healthy individuals.
A systematic review was conducted according to PRISMA guidelines. Searches were performed in the Medline/PubMed, Web of Science, Embase, and ScienceDirect databases to identify studies that assessed surfactants proteins levels in asthmatic patients. Pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using R version 4.4.3 meta package.
A total of 16 studies met the inclusion criteria and were thus considered for this systematic review. Among these, SP-D was the most frequently studied protein in relation to asthma, asthma severity, and lung function parameters in asthmatic patients. Serum and sputum levels of SP-D in asthmatic patients were slightly elevated compared to non-asthmatic individuals. However, these differences were not statistically significant; the pooled SMDs were 0.27 (95% CI: -0.034 to 0.574, P = 0.082) for serum levels and 1.47 (95% CI, -0.197 to 3.103, P = 0.084) for sputum levels. Similarly, no significant difference was detected for the analysis of serum SP-A levels, with SMD = 0.18 (95% CI, -0.505 to 0.866, P = 0.606). Though, some of the reviewed studies showed an association between SP-D levels and disease severity in asthmatic patients.
Although alterations have been observed in asthma and proposed as biomarkers, this systematic review did not find significant differences in the levels between asthmatics and healthy individuals. However, some studies have suggested an association between SP-D levels and asthma severity. Given the limited number of studies investigating this association, further research is needed to validate the clinical relevance of correlation between SP-D levels and asthma severity.
表面活性剂可降低外周气道的表面张力，并在调节肺部免疫反应中发挥作用。多项报告记录了表面活性剂蛋白水平的变化，尤其是表面活性剂蛋白D（SP-D）和表面活性剂蛋白A（SP-A），提示它们作为哮喘生物标志物的潜力。然而，这些研究结果存在争议。本系统评价旨在评估哮喘患者与健康个体相比表面活性剂蛋白的水平。
根据PRISMA指南进行系统评价。在Medline/PubMed、科学引文索引、Embase和ScienceDirect数据库中进行检索，以识别评估哮喘患者表面活性剂蛋白水平的研究。使用R 4.4.3版本的meta包计算合并标准化均数差（SMD）及95%置信区间（CI）。
共有16项研究符合纳入标准，因此纳入本系统评价。其中，SP-D是与哮喘、哮喘严重程度及哮喘患者肺功能参数相关研究中最常涉及的蛋白。哮喘患者血清和痰液中SP-D水平与非哮喘个体相比略有升高。然而，这些差异无统计学意义；血清水平的合并SMD为0.27（95%CI：-0.034至0.574，P = 0.082），痰液水平的合并SMD为1.47（95%CI，-0.197至3.103，P = 0.084）。同样，血清SP-A水平分析未检测到显著差异，SMD = 0.18（95%CI，-0.505至0.866，P = 0.606）。不过，部分纳入研究显示哮喘患者中SP-D水平与疾病严重程度之间存在关联。
尽管在哮喘中已观察到变化并提出作为生物标志物，但本系统评价未发现哮喘患者与健康个体之间的水平存在显著差异。然而，一些研究提示SP-D水平与哮喘严重程度之间存在关联。鉴于研究此关联的研究数量有限，需要进一步研究以验证SP-D水平与哮喘严重程度之间相关性的临床意义。
