Grupo de Unidad de Proteómica, Grupo de Investigación de Reumatología (GIR), Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, Universidade da Coruña (UDC), C/ As Xubias de Arriba 84, 15006, A Coruña, Spain.
The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Imaging Mass Spectrometry, Maastricht University, the Netherlands.
Osteoarthritis Cartilage. 2021 May;29(5):750-761. doi: 10.1016/j.joca.2020.12.025. Epub 2021 Feb 11.
Synovial inflammation is one of the most characteristic events in different types of arthritis, including Osteoarthritis (OA). Emerging evidence also suggests the involvement of lipids in the regulation of inflammatory processes. The aim of this study was to elucidate the heterogeneity and spatial distribution of lipids in the OA synovial membrane and explore their putative involvement in inflammation.
The abundance and distribution of lipids were examined in human synovial membranes. To this end, histological cuts from this tissue were analysed by matrix-assisted laser desorption ionization - mass spectrometry imaging (MALDI-MSI). The lipidomic profile of OA synovium was characterized and compared with healthy and other forms of inflammatory arthropathies as Rheumatoid Arthritis (RA) and Psoriatic Arthritis (PsA) using principal component analysis and discriminant analysis methods. Lipid identification was undertaken by tandem MS analyses and database queries.
Our results reveal differential and characteristic lipidomic profiles between OA and control samples. Specifically, we unveiled that OA synovium presents elevated levels of phosphatidylcholines, fatty acids and lysophosphatidic acids and lower levels of lysophosphatidylcholines compared to control tissues. The spatial distribution of particular glycerophospholipids was also correlated with hypertrophic, inflamed or vascularized synovial areas. Compared with other inflammatory arthritis, the OA tissue showed lower amounts of phosphatidylethanolamine-based plasmalogens.
This study provides a novel insight into the lipid profiles of synovial membrane and differences in abundance between OA and control tissues. The lipidomic alterations improves understanding of the pathogenic mechanisms of OA and may be important for its diagnosis.
滑膜炎症是包括骨关节炎（OA）在内的不同类型关节炎的最典型事件之一。新出现的证据还表明脂质参与炎症过程的调节。本研究旨在阐明 OA 滑膜中脂质的异质性和空间分布，并探讨其在炎症中的潜在作用。
检查了人滑膜组织中的脂质丰度和分布。为此，对该组织的组织学切片进行了基质辅助激光解吸电离 - 质谱成像（MALDI-MSI）分析。使用主成分分析和判别分析方法，对 OA 滑膜的脂质组学特征进行了表征，并与健康组织和其他形式的炎症性关节炎（如类风湿关节炎（RA）和银屑病关节炎（PsA））进行了比较。通过串联 MS 分析和数据库查询进行了脂质鉴定。
我们的结果揭示了 OA 和对照样本之间差异和特征性的脂质组学特征。具体而言，我们发现 OA 滑膜中磷脂酰胆碱、脂肪酸和溶血磷脂酸水平升高，而溶血磷脂酰胆碱水平降低。特定甘油磷脂的空间分布也与肥大、炎症或血管化的滑膜区域相关。与其他炎症性关节炎相比，OA 组织中基于磷脂酰乙醇胺的血浆质的含量较低。
本研究为滑膜膜的脂质谱以及 OA 和对照组织之间丰度的差异提供了新的见解。脂质组学的改变有助于深入了解 OA 的发病机制，可能对其诊断具有重要意义。
