Department of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
United States Army Institute of Surgical Research, JBSA Fort Sam Houston, 3698 Chambers Pass, San Antonio, TX, USA.
Stem Cell Res Ther. 2021 May 6;12(1):270. doi: 10.1186/s13287-021-02327-4.
Patients with severe burn injury (over 20% of the total body surface area) experience profound hypermetabolism which significantly prolongs wound healing. Adipose-derived stem cells (ASCs) have been proposed as an attractive solution for treating burn wounds, including the potential for autologous ASC expansion. While subcutaneous adipocytes display an altered metabolic profile post-burn, it is not known if this is the case with the stem cells associated with the adipose tissue.
ASCs were isolated from discarded burn skin of severely injured human subjects (BH, n = 6) and unburned subcutaneous adipose tissue of patients undergoing elective abdominoplasty (UH, n = 6) and were analyzed at passages 2, 4, and 6. Flow cytometry was used to quantify ASC cell surface markers CD90, CD105, and CD73. Mitochondrial abundance and reactive oxygen species (ROS) production were determined with MitoTracker Green and MitoSOX Red, respectively, while JC-10 Mitochondrial Membrane Potential Assays were also performed. Mitochondrial respiration and glycolysis were analyzed with a high-resolution respirometer (Seahorse XFe24 Analyzer).
There was no difference in age between BH and UH (34 ± 6 and 41 ± 4 years, respectively, P = 0.49). While passage 2 ASCs had lower ASC marker expression than subsequent passages, there were no significant differences in the expression between BH and UH ASCs. Similarly, no differences in mitochondrial abundance or membrane potential were found amongst passages or groups. Two-way ANOVA showed a significant effect (P < 0.01) of passaging on mitochondrial ROS production, with increased ROS in BH ASCs at later passages. Oxidative phosphorylation capacities (leak and maximal respiration) increased significantly in BH ASCs (P = 0.035) but not UH ASCs. On the contrary, basal glycolysis significantly decreased in BH ASCs (P = 0.011) with subsequent passaging, but not UH ASCs.
In conclusion, ASCs from burned individuals become increasingly oxidative and less glycolytic upon passaging when compared to ASCs from unburned patients. This increase in oxidative capacities was associated with ROS production in later passages. While the autologous expansion of ASCs holds great promise for treating burned patients with limited donor sites, the potential negative consequences of using them require further investigation.
严重烧伤患者（超过体表面积的 20%）经历明显的高代谢，这显著延长了伤口愈合时间。脂肪来源干细胞（ASCs）已被提出作为治疗烧伤创面的一种有吸引力的方法，包括自体 ASC 扩增的潜力。虽然烧伤后皮下脂肪细胞的代谢谱发生改变，但与脂肪组织相关的干细胞是否也是如此尚不清楚。
从严重烧伤患者（BH，n=6）废弃的烧伤皮肤和择期行腹部整形术的患者（UH，n=6）的未烧伤皮下脂肪组织中分离出 ASC，并在传代 2、4 和 6 时进行分析。流式细胞术用于定量 ASC 细胞表面标志物 CD90、CD105 和 CD73。使用 MitoTracker Green 和 MitoSOX Red 分别确定线粒体丰度和活性氧（ROS）的产生，同时还进行了 JC-10 线粒体膜电位测定。使用高分辨率呼吸计（ Seahorse XFe24 Analyzer）分析线粒体呼吸和糖酵解。
BH 和 UH 的年龄无差异（分别为 34±6 和 41±4 岁，P=0.49）。虽然传代 2 的 ASC 标志物表达低于后续传代，但 BH 和 UH ASC 之间的表达无显著差异。同样，各组间的线粒体丰度或膜电位也没有差异。双因素方差分析显示，传代对线粒体 ROS 产生有显著影响（P<0.01），BH ASC 在后期传代时 ROS 增加。BH ASC 的氧化磷酸化能力（漏和最大呼吸）显著增加（P=0.035），但 UH ASC 则没有。相反，BH ASC 的基础糖酵解在传代后显著降低（P=0.011），但 UH ASC 则没有。
总之，与未烧伤患者的 ASC 相比，来自烧伤个体的 ASC 在传代时变得更加氧化，糖酵解减少。这种氧化能力的增加与后期传代时 ROS 的产生有关。虽然自体 ASC 扩增在治疗供体部位有限的烧伤患者方面具有巨大的潜力，但使用它们的潜在负面影响需要进一步研究。
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