Division of Medicinal Chemistry and Microbiology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
Wrocław University of Science and Technology, Faculty of Chemistry, Advanced Materials Engineering and Modelling Group, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
Photodiagnosis Photodyn Ther. 2020 Mar;29:101623. doi: 10.1016/j.pdpdt.2019.101623. Epub 2020 Jan 2.
In response to the growing number of life-threatening infections caused by opportunistic Candida albicans fungi we have examined and discussed the effect of glucose and human serum on the efficiency of photosensitization of C. albicans cells with 5-aminolevulinic acid (5-ALA) used as a precursor of protoporphyrin IX (PpIX). We used 630 nm laser diode as an excitation source to enhance the penetration depth and diminish unwanted light scattering, additionally the experiments were performed in planktonic and biofilm cultures to differentiate the results obtained for cells showing various phenotypic characteristics. Based on performed experiments it became obvious that the incubation of C. albicans fungal cells with 5-ALA in the presence of glucose caused a significant increase in concentration of intracellular PpIX, resulting in a higher efficacy of photo-toxic effect. The observed results were rationalized by the role of glucose as an energy source, which supported the active transport of 5-ALA into cells. In contrary to glucose, the presence of human serum caused a significant reduction in PpIX concentration in C. albicans cells with exogenous delivery of 5-ALA, resulting in a less efficient photo-fungicidal effect. In general, the obtained results contributed to the current search for efficient, light activated anti-fungal treatments of high efficiency.
为应对由机会性白念珠菌真菌引起的越来越多的危及生命的感染，我们研究并讨论了葡萄糖和人血清对 5-氨基酮戊酸（5-ALA）作为原卟啉 IX（PpIX）前体的 C. albicans 细胞光致敏效率的影响。我们使用 630nm 激光二极管作为激发源，以增强穿透深度并减少不必要的光散射，此外，还在浮游和生物膜培养物中进行了实验，以区分表现出各种表型特征的细胞的实验结果。根据进行的实验，很明显，在存在葡萄糖的情况下孵育 C. albicans 真菌细胞与 5-ALA 一起导致细胞内 PpIX 浓度显著增加，从而使光毒性作用的效果更高。通过葡萄糖作为能量源的作用，可以合理化观察到的结果，这支持了 5-ALA 向细胞的主动运输。与葡萄糖相反，在存在人血清的情况下，外源添加 5-ALA 的 C. albicans 细胞中 PpIX 浓度显著降低，导致光杀菌作用效率降低。总的来说，所获得的结果有助于当前寻找高效、光激活的抗真菌治疗方法的高效性。
