Musculoskeletal diseases are extremely widespread and a significant burden on the health systems of the industrialized countries. The use of mesenchymal stromal cells is a promising approach to cure cartilage and tendon injuries, which often also occur in younger people as consequences of sport accidents. Although particular interest is on the collagen and the glycosaminoglycan composition of the tendon and potential alterations compared to healthy tissue, there is nowadays also increasing evidence that some selected phospholipids (PL) are potential mediators of tissue regeneration. Therefore, PL (and potential changes thereof) attract increasing interest in this field. We have used positive and negative ion matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) to elucidate the lipid compositions of human mesenchymal stromal cells in dependence on the composition of the cell culture medium and the cultivation time. The de novo biosynthesis of PL was monitored by adding ¹³C labeled glucose or deuterated palmitic acid (d₃₁-PA) to the cells and the incorporation of ¹³C or ²H into the different PL classes was investigated by electrospray ionization (ESI) mass spectrometry (MS). It is remarkable that all PL classes (for instance, phosphatidylcholine and -inositol) exhibited ¹³C incorporation - but not the sphingomyelin (SM) which is the most abundant sphingolipid in the majority of human tissues and body fluids. Using suitable internal standards it could be shown, that only ¹²C-containing SM is de novo generated while no ¹³C-labeled SM could be monitored - independent of the cultivation time, which was varied between 7 and 28 days. SM impurities stemming from the cell culture medium and the used MALDI matrix compounds (2,5-dihydroxybenzoic acid (DHB) or 9-aminoacridine (9-AA)) could be ruled out. However, incorporation of deuterated palmitic acid (d₃₁-PA) could be observed for multiple PL, including SM. Therefore, it is suggested that there must exist another, so far unknown SM biosynthesis pathway. This pathway does not make use of glucose but relies on the use of other molecules as energy sources. Potential pathways to explain the experimental observations are discussed.

肌肉骨骼疾病极为普遍，对工业化国家的卫生系统构成了沉重负担。间充质基质细胞的使用是治疗软骨和肌腱损伤的一种有前途的方法，由于运动事故的后果，这种损伤常在年轻人中发生。尽管特别关注与健康组织相比的腱的胶原蛋白和糖胺聚糖组成以及潜在的改变，但如今也有越来越多的证据表明，某些选定的磷脂（PL）是组织再生的潜在介质。因此，PL（及其潜在的变化）在该领域引起了越来越多的兴趣。我们已经使用正负离子基质辅助的激光解吸/电离飞行时间（MALDI-TOF）质谱（MS）来阐明人间充质基质细胞的脂质成分，具体取决于细胞培养基和栽培时间。的通过向细胞中添加¹³ C标记的葡萄糖或氘代棕榈酸（d ₃₁ -PA）监测PL的从头生物合成，并通过电喷雾电离（ESI）质谱研究了¹³ C或² H掺入不同PL类中的情况（多发性硬化症）。值得注意的是，所有PL类（例如，磷脂酰胆碱和-肌醇）都表现出¹³ C掺入-但不是鞘磷脂（SM），后者是大多数人体组织和体液中最丰富的鞘脂。使用适当的内部标准可以证明，从头生成只有¹² C的SM，而没有¹³可以监测C标记的SM-与培养时间无关，培养时间在7到28天之间变化。可以排除源自细胞培养基和所用MALDI基质化合物（2,5-二羟基苯甲酸（DHB）或9-氨基ac啶（9-AA））的SM杂质。但是，对于包括PL在内的多个PL，可以观察到氘代棕榈酸（d ₃₁ -PA）的掺入。因此，建议必须存在另一种迄今未知的SM生物合成途径。该途径不利用葡萄糖，而是依赖于使用其他分子作为能源。讨论了解释实验结果的潜在途径。