Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt- Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Berlin, Germany.
Lomonosov Moscow State University, Faculty of Physics, Moscow, Russian Federation.
Elife. 2022 Oct 6;11:e72819. doi: 10.7554/eLife.72819.
Macrophages (ΜΦs) are important immune effector cells that promote (M1 ΜΦs) or inhibit (M2 ΜΦs) inflammation and are involved in numerous physiological and pathogenic immune responses. Their precise role and relevance, however, are not fully understood for lack of noninvasive quantification methods. Here, we show that two-photon excited fluorescence lifetime imaging (TPE-FLIM), a label-free noninvasive method, can visualize ΜΦs in the human dermis in vivo. We demonstrate in vitro that human dermal ΜΦs exhibit specific TPE-FLIM properties that distinguish them from the main components of the extracellular matrix and other dermal cells. We visualized ΜΦs, their phenotypes and phagocytosis in the skin of healthy individuals in vivo using TPE-FLIM. Additionally, machine learning identified M1 and M2 MФs with a sensitivity of 0.88±0.04 and 0.82±0.03 and a specificity of 0.89±0.03 and 0.90±0.03, respectively. In clinical research, TPE-FLIM can advance the understanding of the role of MФs in health and disease.
巨噬细胞（ΜΦs）是重要的免疫效应细胞，可促进（M1 ΜΦs）或抑制（M2 ΜΦs）炎症，并参与多种生理和病理免疫反应。然而，由于缺乏非侵入性的定量方法，它们的确切作用和相关性尚不完全清楚。在这里，我们展示了双光子激发荧光寿命成像（TPE-FLIM），一种无标记的非侵入性方法，可以在体内可视化人类真皮中的ΜΦs。我们在体外证明，人类真皮ΜΦs 表现出特定的 TPE-FLIM 特性，可将其与细胞外基质的主要成分和其他真皮细胞区分开来。我们使用 TPE-FLIM 在体内可视化了健康个体皮肤中的 ΜΦs、它们的表型和吞噬作用。此外，机器学习以 0.88±0.04 和 0.82±0.03 的灵敏度和 0.89±0.03 和 0.90±0.03 的特异性分别识别 M1 和 M2 MФs。在临床研究中，TPE-FLIM 可以促进对 MФs 在健康和疾病中的作用的理解。
