Morphological effects of photodynamic therapy for atherosclerotic vascular lesions (pilot ex vivo study)

   Photodynamic therapy (PDT) is considered a promising method for modifying atherosclerotic plaques through selective photo-oxidative damage to their structural components while preserving intact areas of the vascular wall. The morphological changes induced by PDT have direct clinical relevance, as they are associated with plaque stability and the risk of thrombosis; therefore, their characterization is essential for optimizing treatment parameters and improving the safety of the method. The aim of this study was to evaluate the morphological effects of PDT on human aortic atherosclerotic lesions ex vivo using the chlorin e6–based photosensitizer Photolon. It was shown, that photodynamic therapy with chlorin e6 ex vivo induces selective destruction of the organic components of atherosclerotic plaques while preserving the structural integrity of intact vascular wall layers. The absence of macroscopic reduction in plaque size after a single treatment reflects the resistance of the collagenous and calcified framework. These findings confirm the selective action of PDT and indicate the need for further in vivo studies to evaluate the temporal dynamics of plaque remodeling and potential delayed volume reduction.

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